Informal Preview of Geo-Spatial Analysis Project

[String]

Just a couple of questions.
Are these distances as the crow flies?
I thought that the distances would be skewed a bit if we took into account actual walking distances on the ground. This would include alley ways that may have been used as short cuts.
Could you also not then use walking times rather than distances as the murderer might be more mindful of the amount of time that he was abroad rather than distance he has travelled? I know if I'm out walking I judge it by time rather than by distance as I can measure time more easily.
Interesting stuff BTW.

[Septic Blue]

It seems to me that the Goulston Street graffito location should not just be taken into consideration as a data point. From the layman's perspective, and according to common sense, the location of the GSG indicates more than just a data point, since it indicates the direction walked by the perpetrator after the Eddowes murder, and likely suggests the direction of the killer's residence. It seems to me that any mathematical model would take this into consideration... admittedly I have no idea HOW this would be incorporated into a geo profile model such as this...

Hi Rob,

I think the spirit of objectivity would invariably dictate that the apron 'deposit' be perceived as a component of the Eddowes 'observation', i.e. the Eddowes 'data point'; such that any 'weight' of factorization given to the Goulston Street doorway, would have to be taken away from the Mitre Square murder-site.

On the other hand; these distributions can be assembled with as much subjectivity as one deems applicable. The doorway in Goulston Street could be added to the distribution as a complete 'observation' / 'data point' in itself; and the axes of ellipse-orientation could be rotated to accommodate the direction of 'egress' that the apron 'deposit' seems to suggest. But again; this would be very subjective in its application, and would therefore, not be suitable for my purposes.

… I am unclear why an ellipse is being used at all, as opposed to a circle or any other shape. It seems rather arbitrary. Is it because the spatial distribution of sites is longer than it is high (so to speak)?

Figure 1: Standard Deviation Circle / Ellipse (Click to View in flickr)
Underlying Aerial Imagery: Copyright Google Earth, 2007
Overlying Plots, Labels and Color-Shadings: Copyright Colin C. Roberts, 2009

The 'Mean-Center' (i.e. the murder-site epicenter) and 'Standard Deviation Circle' provide the most efficient description of the murder-site distribution, attainable by way of just two 'statistics'. I will be explaining the concept (and methods of calculation) of 'Standard Deviation' in my forthcoming formal presentation; using of course, layman-terminology. Hopefully then; this will make sense.

A shortcoming however, of the 'Standard Deviation Circle', is its inability to account for any directional bias or 'skew' that might be evident in the distribution of 'observations'. Specifically, in this case (as you rightfully noted); the "distribution of sites is longer than it is high (so to speak)". It is also 'tilted'; but the 'Circle' accounts for neither of these two attributes.

The use of the 'Standard Deviation Ellipse' is conceptually akin to stretching the corresponding 'Circle' in its two directions of 'greatest aggregate dispersion' (in this case: 54.47°; 234.47°), while watching it shrink accordingly from its two directions of 'least aggregate dispersion' (in this case: 144.47°; 324.47°); in order to make it describe the distribution more accurately. As such; the 'Ellipse' (i.e. the actual curve) depicts a constant degree or 'magnitude' of deviation from the murder-site epicenter, regardless of applicable distance. In other words: Any point on the green ellipse can be seen conceptually as being of 'equal' deviation from the murder-site epicenter.

It seems the actual spatial distribution of the sites is somewhat lopsided (weighted to the west)... I am picturing a more amorphous blob.

If we were to analyze the distribution of murder sites as a set of two-to-three clusters or 'kernels', such that a similar number of ellipses of varying size and orientation were 'merged', in order to describe the entire distribution; then we would in fact, be seeing an "amorphous blob".

The complex models used by geographic profilers such as Kim Rossmo, David Canter, Ned Levine (CrimeStat), et al …, would also each generate an "amorphous blob".


'Screen-Capture' (photograph of television screen) from "Revealed" Jack the Ripper: The First Serial Killer (2006)

A Portion of Kim Rossmo's 'Criminal Geographic Target' (i.e. his proprietary geographic profile), for the 'MacNaghten-Five' Victims of 'Jack the Ripper'

Rossmo's 'CGT' designates a rectangular 'search area' that is divided into 40,000 'cells'; to each of which a proprietary 'distance-decay' function (including empirically derived constants and exponents) is applied. Each 'cell' is thereby assessed as to its likelihood of having played host to the residence of 'Jack the Ripper'. The 'probability distribution' in this case, is indeed an "amorphous blob".

Note the three 'peaks' of relatively high probability density (red):

- The vicinity of the southeast corner of New Goulston Street / Middlesex Street, Parish of St. Mary Whitechapel

- The vicinity of the southwest corner (Lolesworth Buildings) and northeast corner of George Street / Thrawl Street, Parish of Christ Church Spitalfields ***

- The vicinity of the northeast corner of Osborn Place / Brick Lane, (Boundary) Parishes of St. Mary Whitechapel & Christ Church Spitalfields

*** Rossmo described this, the 'highest' of the three 'peaks', in the following manner:

"… the peak area, where the profile is falling on, covers Flower & Dean Street, Fashion Street, Thrawl Street, …"

We have somehow interpreted this to mean that, according to Rossmo: "'Jack the Ripper' probably lived on Flower & Dean Street".

This is a significant misrepresentation of Rossmo's 'conclusions'; especially in light of the fact that the red portion of this 'peak' barely comes into contact with Flower & Dean Street – doing so, only in the immediate vicinity of #5, a large doss house on the south side of the thoroughfare, opposite #56 (the 'White House').

Rossmo's model would actually suggest that the 'highest' point (i.e. the immediate vicinity of Lolesworth Buildings), within this, the 'highest peak'; would be the single most likely residence of 'Jack the Ripper'. That is a 'far cry' from suggesting that he probably lived there.

Note also, the two 'valleys' of relatively low probability density (blue):

- The vicinity of the intersection of Dorset Street / Crispin Street, Parish of Christ Church Spitalfields

- The vicinity of Whitechapel Road; from Osborn Street / Church Lane –to- Black Lion Yard / Fieldgate Street, Parish of St. Mary Whitechapel

[Chris]

Rossmo's 'CGT' designates a rectangular 'search area' that is divided into 40,000 'cells'; to each of which a proprietary 'distance-decay' function (including empirically derived constants and exponents) is applied.

My impression is that these functions containing empirically determined parameters will be appropriate (if at all) only to modern cases in which the killer travels over a large area by car, and won't tell us anything at all about a 19th-century case in which he most likely travelled over a small area on foot.

[John Bennett]

I have just been catching up on this thread and from looking at the analysis of x and y axis data points, empirically determined parameters, standard deviation circles, mean centres, least aggregate dispersions, distance decay functions, cumulative distribution functions and foci eccentricity, I have been able to draw a singular conclusion:

And that is that my brain hurts.

[Septic Blue]

Rossmo's 'CGT' designates a rectangular 'search area' that is divided into 40,000 'cells'; to each of which a proprietary 'distance-decay' function (including empirically derived constants and exponents) is applied.

My impression is that these functions containing empirically determined parameters will be appropriate (if at all) only to modern cases in which the killer travels over a large area by car, and won't tell us anything at all about a 19th-century case in which he most likely travelled over a small area on foot.

I agree wholeheartedly, Chris! When one considers the possibility that thousands of 'local' residents, like Charles Lechmere (a.k.a. "Charles Cross"), traversed the entire 'killing field' as a matter of daily routine; the application of an extremely complex 'distance-decay' function - utilizing empirically derived constants and exponents - to each of some 40,000 rectangular 'cells', on the basis of just five-or-six data points, smacks of 'milking' what little information we have for infinitely more than it is worth.

And; as I have already stated:

While I truly believe that the Probability Distribution, which I have depicted, and the 'Geo-Profile' Probability Distribution that I have actually created, both afford invaluable perspectives; I must acknowledge that they may simply be 'profiling' the residences and 'activity spaces' of the victims, while indicating very little about the killer(s).

[Jon Guy]

Hello Colin

Would working the victims times of death into the figures show us anything ?

ie. We know the killer was in Hanbury St between 05.00 am and 05.30 am etc etc ?

[Chris]

I agree wholeheartedly, Chris! When one considers the possibility that thousands of 'local' residents, like Charles Lechmere (a.k.a. "Charles Cross"), traversed the entire 'killing field' as a matter of daily routine; the application of an extremely complex 'distance-decay' function - utilizing empirically derived constants and exponents - to each of some 40,000 rectangular 'cells', on the basis of just five-or-six data points, smacks of 'milking' what little information we have for infinitely more than it is worth.

And; as I have already stated:
While I truly believe that the Probability Distribution, which I have depicted, and the 'Geo-Profile' Probability Distribution that I have actually created, both afford invaluable perspectives; I must acknowledge that they may simply be 'profiling' the residences and 'activity spaces' of the victims, while indicating very little about the killer(s).

I think both those statements are true, but the point I was making is a rather different one.

The profilers are using complicated functions that depend on empirically determined parameters. But even if one assumes the approach is valid, there is no reason to think the parameters that have been determined for 20th-century murderers travelling by car are the same ones that would apply to a 19th-century murderer travelling on foot. So even in their own terms, in applying their computer models to the Whitechapel Murders they are probably using the wrong parameters, and therefore getting the wrong probability distribution.

[Septic Blue]

… the point I was making is a rather different one.

The profilers are using complicated functions that depend on empirically determined parameters. But even if one assumes the approach is valid, there is no reason to think the parameters that have been determined for 20th-century murderers travelling by car are the same ones that would apply to a 19th-century murderer travelling on foot. So even in their own terms, in applying their computer models to the Whitechapel Murders they are probably using the wrong parameters, and therefore getting the wrong probability distribution.

I see your point, Chris; and I certainly concur.

The utilization of empirically derived parameters imposes a 'twentieth-century perspective' upon what ought to be a 'nineteenth-century solution'.

Would working the victims times of death into the figures show us anything ?

There are methods of factoring the chronology of a series of events into a geo-spatial analysis, Jon. But doing so, in this instance, would not suit my purposes.

As for the times of death: I suppose that unusually 'early' events (e.g. the Stride Murder) and/or unusually 'late' events (e.g. the Chapman Murder) could be assigned different 'weights' of factorization, accordingly. But this would require subjective reasoning, which too in this instance, would not suit my purposes.


Figure 1: Immediate Vicinity; General Vicinity; Broad Vicinity (Click to View in flickr)
Underlying Aerial Imagery: Copyright Google Earth, 2007
Overlying Plots, Labels and Color-Shadings: Copyright Colin C. Roberts, 2009

Please remember; my overall objective is the establishment of a set of parameters that will define the 'landscape' of this series of atrocities, and more-or-less determine those persons, places and things, which were 'local' thereto.

As such; I don't feel as if I could reiterate the following 'too often':

While I truly believe that the Probability Distribution, which I have depicted, and the 'Geo-Profile' Probability Distribution that I have actually created, both afford invaluable perspectives; I must acknowledge that they may simply be 'profiling' the residences and 'activity spaces' of the victims, while indicating very little about the killer(s).

Are these distances as the crow flies?
I thought that the distances would be skewed a bit if we took into account actual walking distances on the ground. This would include alley ways that may have been used as short cuts.

Yes! All applicable distances/measurements (to be fully delineated in my forthcoming formal presentation) are 'straight-line'.

Unfortunately; determining the most 'applicable' routes would be 'guess-work'.

[Septic Blue]

Note: In order to facilitate a more 'obvious' link to each applicable flickr image; I will henceforth provide access by way of a 'click' on the respective 'flickr' - and by way of a 'click' on the respective 'thumbnail' image, itself.

… one thing that struck me is that the site of Tabram's murder is so close to the "epicentre" that the predicted distribution would be reasonably similar if she were excluded. Unfortunately the same won't be true of Stride.

Quite right, Chris! The removal of Tabram would shift the epicenter a grand total of 20.53 yards east/northeast to the western 'mouth' of Old Montague Street; whereas the removal of Stride would shift the epicenter north/northwest to the vicinity of the 'White House', on Flower & Dean Street.

The real 'eye-opener' regarding Stride, can be seen in the progression from the circular perspective …


Figure 2: Deviations from Murder Site Epicenter (Circular) (Click to View in flickr)
Underlying Aerial Imagery: Copyright Google Earth, 2007
Overlying Plots, Labels and Color-Shadings: Copyright Colin C. Roberts, 2009

… to the elliptical perspective.


Figure 9: Deviations from Murder Site Epicenter (Elliptical) (Click to View in flickr)
Underlying Aerial Imagery: Copyright Google Earth, 2007
Overlying Plots, Labels and Color-Shadings: Copyright Colin C. Roberts, 2009

Notice that the relative positions of Stride and Eddowes are switched, in going from 'circular' to 'elliptical'.

The elliptical perspective, which accounts for the 'mobility' provided by Aldgate High Street / Whitechapel High Street / Whitechapel Road, as well as role that the thoroughfare might have played as a 'barrier' in the minds of the victims or killer (or both); suggests that even though Dutfield's Yard was in closer proximity to the murder-site epicenter than was Mitre Square, it should have been viewed as a less likely venue for the impending subsequent murder, following the death of Mary Jane Kelly.

One thing I wondered was whether the calculated eccentricity is statistically significant, given the small sample size. Even if there were an underlying centrally symmetrical distribution, sampling would produce an asymmetrical distribution, and therefore an eccentric ellipse. The smaller the sample, the larger this artefactual eccentricity would be.

I believe that 'sampling error' could affect both foci-eccentricity and axis-orientation.

I am also skeptical of the practicality in using the 'Elliptical Perspective' to depict a distribution beyond ~two standard deviations. As such; I am contemplating a model, in which foci-eccentricity actually increases (to a specified limit) below the 'threshold' of one standard deviation, and decreases (to '0') beyond the same 'threshold'.

While in the process of preparing a formal presentation of my analysis, which I plan to begin posting in the next three-to-four weeks; I have continued to develop some of the 'Elliptical Perspective' imagery that was 'in progress' when I initiated this thread. In so doing, I believe that I may have 'enhanced' my own perspective of the Stride murder-site, relative to its placement within the overall murder-site distribution.


Figure 1: Incremental Probability Distribution (0.00 - 3.00 Standard Deviations) (Circular) (Click to View in flickr)
Underlying Aerial Imagery: Copyright Google Earth, 2007
Overlying Plots, Labels and Color-Shadings: Copyright Colin C. Roberts, 2009


Figure 2: Incremental Probability Distribution (0.00 - 3.00 Standard Deviations) (Elliptical) (Click to View in flickr)
Underlying Aerial Imagery: Copyright Google Earth, 2007
Overlying Plots, Labels and Color-Shadings: Copyright Colin C. Roberts, 2009

Remember that in accordance with my 'geo-profile' model; one standard deviation is the '50%-threshold', i.e. the point, at which there is a perceived 'probability' of 63.68% that the murderer would continue to kill within (assuming he were to continue); and therefore a 31.84% perceived 'probability' that the he would be found to be living within (assuming he were to be found).

Again:

"… the removal of Stride would shift the epicenter north/northwest to the vicinity of the 'White House', on Flower & Dean Street."

"… even though Dutfield's Yard was in closer proximity to the murder-site epicenter than was Mitre Square, it should have been viewed as a less likely venue for the impending subsequent murder, following the death of Mary Jane Kelly."

"I am also skeptical of the practicality in using the 'Elliptical Perspective' to depict a distribution beyond ~two standard deviations."

As Whitechapel High Street becomes 'Whitechapel Road', it begins to extend in a more-easterly / less-northeasterly direction; thus rendering the orientation of the elliptical probability distribution (i.e. the orientation of its major axis) less 'suitable' – assuming, of course, that the elliptical perspective does indeed account for the 'mobility' provided by Aldgate High Street / Whitechapel High Street / Whitechapel Road.

Therefore, in this particular instance; "the practicality in using the 'Elliptical Perspective' to depict a distribution beyond ~two standard deviations" is clearly quite limited.

Specifically; with regard to the Stride murder-site:

While it is extremely difficult to simply 'eyeball' this sort of thing with any degree of accuracy; I believe that the removal of the Stride murder-site would precipitate a clockwise rotation of the 'Elliptical Perspective', such that its orientation would coincide more closely with the orientation of the entire thoroughfare 'Aldgate High Street / Whitechapel High Street / Whitechapel Road'. Of course, I will have to generate some actual calculations/measurements, before knowing that this is indeed the case. But, assuming it to be so; this could be seen - from a subjective perspective, of course – as yet another indication that the Stride murder-site just 'doesn't belong'.

In any case:

Since I am "skeptical of the practicality in using the 'Elliptical Perspective' to depict a distribution beyond ~two standard deviations"; "I am contemplating a model, in which foci-eccentricity actually increases (to a specified limit) below the 'threshold' of one standard deviation, and decreases (to '0') beyond the same 'threshold'".


Figure 3: Immediate Vicinity; General Vicinity; Broad Vicinity (Click to View in flickr)
Underlying Aerial Imagery: Copyright Google Earth, 2007
Overlying Plots, Labels and Color-Shadings: Copyright Colin C. Roberts, 2009

Such a model would incorporate a somewhat elliptical estimation of 'immediate vicinity' (red); a slightly elliptical estimation of 'general vicinity' (aqua); and a mostly unchanged estimation of 'broad vicinity' (purple).


Figure 4: Ancient Parochial Establishment of East London (Click to View in flickr)
Underlying Aerial Imagery: Copyright Google Earth, 2007
Overlying Plots, Labels and Color-Shadings: Copyright Colin C. Roberts, 2009

Part of an effort to define that, which was 'local' in the context of political geography:

- Bright Yellow: St. John at Hackney
- Orange: St. Leonard Shoreditch
- Red: St. Dunstan Stepney
- Green: Bromley St. Leonard
- Purple: City of London
- Gold: The Liberty of His/Her Majesty's Tower of London
- Blue: Precinct of the Priory of St. Mary without Bishopsgate (St. Mary Spital)
- Green: Precinct of the Priory of the Holy Trinity, Aldgate (County of Middlesex)

The Ancient Parish of St. Dunstan Stepney (Red) was divided, between the years 1329 - 1817, into the following Civil Parishes:

- St. Matthew Bethnal Green
- Christ Church Spitalfields
- The Hamlet of Mile End New Town
- St. Mary Whitechapel
- St. John of Wapping
- St. George in the East
- St. Paul Shadwell
- The Hamlet of Mile End Old Town
- The Hamlet of Ratcliff
- St. Anne Limehouse
- St. Mary Stratford Bow
- All Saints Poplar

The Precinct of the Priory of St. Mary without Bishopsgate (St. Mary Spital) (Blue) was originally part of St. Botolph without Bishopsgate (excepting the northernmost 'tip', which was part of St. Leonard Shoreditch). By the end of the seventeenth century, it had become The Liberty of Norton Folgate (north) and The Old Artillery Ground (south).

The green areas, which constituted the Middlesex portions of the Precinct of the Priory of the Holy Trinity, Aldgate were originally part of St. Botolph without Aldgate. The smaller area (north) eventually became Holy Trinity (Minories), while the larger area (south) became The Precinct of St. Katharine (west), and once again St. Botolph without Aldgate (east).

Unlike the similar image shown in earlier posts; the above overlay depicts the Parish of St. John at Hackney in its entirety.


Figure 5: Murder-Site 'Vicinity' in the Context of a Larger 'East End' (Click to View in flickr)
Underlying Aerial Imagery: Copyright Google Earth, 2007
Overlying Plots, Labels and Color-Shadings: Copyright Colin C. Roberts, 2009

Red Outline and Portions of White-Dotted 'Compensation' Outline: An estimation of the area most likely to have been considered the 'East End', in 1888

The Parliamentary Borough of Shoreditch
- The Parish of St. Leonard Shoreditch

The Parliamentary Borough of Bethnal Green
- The Parish of St. Matthew Bethnal Green

The Parliamentary Borough of Tower Hamlets
- The Liberty of Norton Folgate
- The Old Artillery Ground
- The Parish of Christ Church Spitalfields
- The Hamlet of Mile End New Town
- The Parish of Holy Trinity (Minories)
- The Parish of St. Mary Whitechapel (Middlesex portion)
- The Liberty of Her Majesty's Tower of London
--- The Liberty of the Tower
--- The Precinct of Old Tower Without
--- The Tower
- The Precinct of St. Katharine
- The Parish of St. Botolph without Aldgate (Middlesex portion)
- The Parish of St. John of Wapping
- The Parish of St. George in the East
- The Parish of St. Paul Shadwell
- The Hamlet of Mile End Old Town
- The Hamlet of Ratcliff
- The Parish of St. Anne Limehouse
- The Parish of St. Mary Stratford Bow
- The Parish of Bromley St. Leonard
- The Parish of All Saints Poplar

My analysis would suggest that a sizable portion of 1888's 'East End' was not 'local' to this series of murders; and that a sizable portion of the area, which was 'local' to this series of murders was not in the 'East End'.

[Scott Nelson]

...And, enstatite facies metamorphism...

[caz]

Hi Colin,

While I admire anyone who puts in this amount of work on the subject, I can't help wondering how 'invaluable' it could ever prove, considering your own caveats:

While I truly believe that the Probability Distribution, which I have depicted, and the 'Geo-Profile' Probability Distribution that I have actually created, both afford invaluable perspectives; I must acknowledge that they may simply be 'profiling' the residences and 'activity spaces' of the victims, while indicating very little about the killer(s).

Conversely; the directional bias or 'skew' of the murder-site distribution could be indicative of a killer who felt uncomfortable veering too far off of the main 'arteries', for lack of an acute familiarity with the area.

Without knowing why the killer would keep on murdering and mutilating unfortunates at all, with growing numbers of police, vigilance committee members and the general public on his tail, it's simply not possible to determine what factors did or didn't go into his decision to do it yet again, in the November, in the heart of Spitalfields. Any number of psychological factors could have been involved, that might have combined to lure him into the same area that had recently become notorious for the particularly hideous deaths of Emma Smith and Martha Tabram, and to keep him there for the Autumn of Terror, regardless of whether or not he already happened to be on the spot at the start of this dreadful year, and for the first of these unusually brutal crimes against street women. Current or previous familiarity with the area - and perhaps with this specific victim type too - could have added to the magnetic effect.

The problem, as I see it, is that the spectre of the serial offender who couldn't be doing with the rule book can't be wished away using probability. Colin Ireland merrily went about his business, picking up each of his victims from the same gay pub in Fulham, and going back to their home, wherever that happened to be, to kill them, without sparing a thought for the poor mathematician trying to work out his probable location from the available data.

If the pub represented Colin Ireland's centre of operations, and the victims all lived within a certain radius, representing a reasonable travelling distance on foot or by public transport from home to this particular watering hole, what kind of mathematical wizard would have been needed to work out that their killer was probably scraping together his train fare each time and coming up from Southend-On-Sea in Essex, to pick up one customer after another from this one pub in south-west London?

Colin Ireland's reasoning had nothing to do with where he could expect to find his nearest supply of easy victims; nothing to do with where he lived in relation to his chosen victims; and nothing to do with being forced to select all his prospective victims from one small geographical area. To ignore cases like his as improbable, and therefore to focus away from all the probable factors behind such reasoning, is to risk putting the focus on a whole lot of work done for absolutely nothing.

Love,

Caz
X

[Ben]

Hi Caz,

Colin Ireland didn't murder and dispose of his victims within a tiny, easily walkable locality. His "criminal map" was conditioned by greater opportunities in terms of transport, in the way that Jack the Ripper's was almost certainly conditioned by a lack of them. Since murder locations constitute the chief criterion for creating a geographic profile, and not where the killer first encountered his victims, I don't see how Ireland somehow militates against the principles of geo-profiling.

Best regards,
Ben

[Septic Blue]

Caz,

I'm sure you will realize that I 'assembled' this post before knowing that you had entered the discussion (here, on Casebook).

------------

It would appear, unfortunately, that 'Geographic Profiling' is widely misunderstood. From the misconception that all geographic profiles are essentially homogeneous in their methodologies and reasoning (such that they invariably conclude that the perpetrator operated from within his 'killing field'); to the assumption that Kim Rossmo's Criminal Geographic Target analysis of the 'Macnaghten Five' murder sites suggested that the killer probably resided in Flower & Dean Street (his 'CGT' analysis suggested no such thing): 'Geographic Profiling' has been misunderstood, misrepresented and accordingly referred to as "pointless", "nonsense" and "rubbish" – by those who know absolutely nothing about the field.

While 'Geographic Profiling' can certainly be taken to excessive levels of micro-analysis; …

When one considers the possibility that thousands of 'local' residents, like Charles Lechmere (a.k.a. "Charles Cross"), traversed the entire 'killing field' as a matter of daily routine; the application of an extremely complex 'distance-decay' function - utilizing empirically derived constants and exponents - to each of some 40,000 rectangular 'cells', on the basis of just five-or-six data points, smacks of 'milking' what little information we have for infinitely more than it is worth.

… and into the realm of the 'inappropriate' …

… the point I was making is a rather different one.

The profilers are using complicated functions that depend on empirically determined parameters. But even if one assumes the approach is valid, there is no reason to think the parameters that have been determined for 20th-century murderers travelling by car are the same ones that would apply to a 19th-century murderer travelling on foot. So even in their own terms, in applying their computer models to the Whitechapel Murders they are probably using the wrong parameters, and therefore getting the wrong probability distribution.

I see your point, Chris; and I certainly concur.

The utilization of empirically derived parameters imposes a 'twentieth-century perspective' upon what ought to be a 'nineteenth-century solution'.

… it can also be used to great effect:

- John Snow's successful identification of the source of a cholera epidemic that claimed more than seven hundred lives in the span of just three-to-four weeks, in the vicinity of Broad Street, (Soho) Parish of St. James Westminster, in 1854

- Charles Booth's somewhat successful (?) identification of the sources of poverty throughout London's metropolis (through detailed descriptions of its locations and manifestations), in a seventeen-year survey (1886-1903), which produced the following: Map Shewing Degrees of Poverty in London 1889-1891; Descriptive Map of London Poverty 1889-1891; and Maps Descriptive of London Poverty 1898-1899


Figure 1: Map Shewing Degrees of Poverty in London 1889-1891
Click Image to View in Harvard University Library – Image Delivery Service


Figure 2: Descriptive Map of London Poverty 1889-1891
Click Image to View in Harvard University Library – Image Delivery Service

Those who would sneer therefore, at the overall concept of 'Geographic Profiling', should begin by belittling the remarkable contributions of these two gentlemen.

Would Geo Spatial Analyisis applied to Ted Bundy Anywhere in his sequence result in a positive identification .. ok .. obtuse but my point is clear

Spoken like a true 'philistine'!

And, speaking of 'philistines' …

[ATTACH]5424[/ATTACH] - Click 'Quote Prompt' (white arrow) to view in JTR Forums.com –

[ATTACH]5424[/ATTACH] - Click 'Quote Prompt' (white arrow) to view in JTR Forums.com –

In the same way, if the distances used in this analysis have no relationship to distance as JtR would have experienced it (him not being able to go through cement).....then any analysis based on that erroneous measure of distance is ....... pointless.

And of course, if JtR’s victims dictated both the distance and direction of his travelling experience from their mutual pick-up point, it’s even more pointless. Or perhaps he would have stubbornly refused to walk a few more paces with any prospective victim, or a single pace in one direction rather than another, on the grounds that it would sod up the geographical profilers of the future if his victims’ movements had given no clear indication of where he most likely laid his hat on the many nights he wasn’t out with his freshly sharpened knife looking for a bit of mutilating action.

… if you stand beside one, on top of his empty soapbox; you're going to start sounding like one, yourself.

And, BTW; (not that it matters, one way or the other) …

"… if JtR’s victims dictated both the distance and direction of his travelling experience from their mutual pick-up point, …"

This will always be an "IF"! We shouldn’t presume to know things that we plainly and simply do not know: Especially, when they are based entirely on supposition.

Now; where was I? …

As I have embraced a traditional and widely used facet of 'Geo-Spatial Analysis' (specifically, in this instance; an analysis of the central tendency of the distribution of murder sites most closely associated with 'Jack the Ripper'), and because I have taken the additional step of actually creating my own 'geographic profile' model – all for the sake of enhancing our understanding of the landscape, in which these murders were committed, and establishing a set of parameters for defining our use of the term 'local'; I have apparently been associated with those who would have us believe that 'Jack the Ripper' undoubtedly lived within his own 'killing field'.

- Again (I don't think this can be stated too often):

"… all for the sake of enhancing our understanding of the landscape, in which these murders were committed, and establishing a set of parameters for defining our use of the term 'local'; …"

[ATTACH]5424[/ATTACH] - Click 'Quote Prompt' (white arrow) to view in JTR Forums.com -

I've not read the casebook post(s) in question yet, but it always seems to me that the sample of murder locations we deal with has at least as much to do with the victims' behavioural patterns as that of their killer(s), and arguably a lot more.

It's not like the ripper carted the bodies off to some place entirely of his own choosing, that might then conceivably indicate some special geographical relationship between his crimes and where he might be found when not committing them. Depending on means and opportunity, for instance, one killer might let the bodies pile up in his own home or back yard, while another might try to dump them as remotely as possible.

But in this case we keep coming back to the realistic possibility that the killer was lazy and practical and was happy for his victims to be found dead in the places where it had suited their purposes to be at the time, or to go.

Even if we could be sure of where he was when he initially encountered each victim (for instance, cruising two or three main roads for particularly desperate specimens) it would still be down to why the women were there to be encountered. It wouldn't necessarily tell us a damned thing about where the killer was most likely to have had his abode, fixed or otherwise.

It may come as a surprise Caz (although I don't know why it should); but I wholeheartedly agree with the entirety of your post. Most especially its conclusion: "… it would still be down to why the women were there to be encountered. It wouldn't necessarily tell us a damned thing about where the killer was most likely to have had his abode, fixed or otherwise."

[ATTACH]5424[/ATTACH] - Click 'Quote Prompt' (white arrow) to view in JTR Forums.com –

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The fact that he centred his activities around one small region may have something important to tell us about the general area in which he lived.

Indeed, Sam - but we’ll never know what we are being told or how important it is from plotting the victims’ short journeys with Jack to meet their maker. He may be telling us that the general area in which he lived (on a permanent basis) had a few too many people who might recognise him, or far too few potential victims parading the streets alone at night, to make hunting there remotely practical. And that would be rather important, I would think.

The small region you speak of did after all boast an infamous reputation (whether you think it was deserved or not) for large numbers of the most vulnerable and endangered game birds known to man or beast, who tended to flock there and go to pot when life pooped on them.

He could have been reasonably familiar with the general area for a million and one reasons, or even made it his business to test the especially seedy reputation of its seedier parts for accuracy. Even if you could show there were greater mutilating opportunities elsewhere for a killer ‘like Jack’, you will be stuffed as soon as you try to argue that Jack’s repetitive behaviour towards frail, sick, alcoholic, downtrodden, desperately poor bag ladies would only have extended to using the same small hunting ground time after time if his own wings were well and truly clipped. There is zero evidence to tell you any such thing, and quite a bit of evidence of other serial killers adopting very small and specific hunting grounds, not because they were fortunate enough to live smack in the middle of particularly fruitful ones, but because their fruitfulness was tried and tested and happened to tick all the right boxes.

My argument is not that Jack is more likely to have lived elsewhere and made the small area around Dorset St his ‘territory’ for the marking. My argument is that the evidence allows him to have done precisely that, just as it allows him to have had his perch there all along, with tuppence to feed the poor birds who settled there and came starving to him. So I can’t see that ‘the paucity of evidence that confronts us’ would make plumping for the local perch scenario a better option than plumping for neither. If you plump at all, you could be plumping for going miles in completely the wrong direction. …

Likewise; I wholeheartedly agree with the above portion of your subsequent post.

As I have indicated on other long-lost threads, my research has given me the distinct impression that London's East End did not have any semblance of a monopoly, where poverty, vice and criminal behaviour within the metropolis were concerned. This of course, is contrary to today's 'conventional wisdom', as well as that of 1888. Charles Booth, himself, was quite surprised by the amount of poverty that his research team uncovered in areas like Greenwich, Bermondsey, Southwark, Holborn and Clerkenwell. In fact, he eventually concluded that the Southwark Parishes of Christ Church, St. Saviour and St. George the Martyr were the most impoverished in the whole of the metropolis.

Considerable wealth and abject poverty both tended to be concentrated in various enclaves throughout the four 'quarters' (North, East, South, and West) of London's metropolis in 1888; with two notable exceptions: Certain parts of the West End, which were too large to be considered mere 'enclaves', enjoyed considerable wealth; while nowhere in the East End was such wealth at all prevalent. The only characteristic of the East End, which truly differentiated it from the other 'quarters' of the metropolis, was just that: An apparent lack of any enclaves of considerable wealth. The East End was a massive sea of 'blue collar' society, having just slightly more than its fair share of enclaves of abject poverty, vice and criminal elements.

Three of these enclaves were found in the Civil Parish of Christ Church Spitalfields:

Great Pearl Street
- Great Pearl Street
- Little Pearl Street

Dorset Street
- Dorset Street
- Little Paternoster Row

Flower & Dean Street
- Flower & Dean Street (excepting its southwestern quarter)
- George Street (eastern side)
- Thrawl Street (eastern half)
- Wentworth Street (between George Street and Brick Lane)
- George Yard (northeastern quarter)

I am inclined to believe that two of them, namely Dorset Street and Flower & Dean Street, were most unusual in that they were apparently home to an extraordinarily large concentration of a particular type of prostitute: The middle-age, alcoholic, totally destitute and completely vulnerable 'dolly-mop' (amateur).

I have little doubt that had these murders continued indefinitely, the epicenter of their locations would have gradually moved into increasingly closer proximity to the epicenter of the two enclaves mentioned above (i.e. Dorset Street and Flower & Dean Street); regardless of the location of the perpetrator's 'base'. In other words: I am of the opinion that the distribution of murder sites, in this case, is mostly a function of the tightly clustered locations of the victims' residences.

Now that we are discussing the subject of geographic profiling:

"If the area covered by a series of crimes is circumscribed, then in the majority of cases the serial offender has a base of some sort within that area. Let me hasten to add that this is not true in all cases, and the proportion of offenders who live within this 'criminal range' varies considerably depending on many aspects of the crimes and locations. But as a rule of thumb there is at least a 50-50 chance that the offender lives within the area defined by a circle that joins the two furthest crimes. If the spread of the crime is great and the criminal thinks he may be recognized in a given location then the chance he lives within this circle increases. If the criminal is clearly targeting a particular type of criminal opportunity then the chance will decrease because it is the opportunity for the crime that determines where he will offend, rather than the location of his base. There is thus the real possibility that Jack came into the area because of the opportunities available to carry out his mission. But the distribution of the crimes around the small area, together with their timing, also offers the possibility that he had a base in the area."David Canter, Mapping Murder, p. 131.

Take a good long look at that, folks.

"If the criminal is clearly targeting a particular type of criminal opportunity then the chance (that the offender lives within the area) will decrease because it is the opportunity for the crime that determines where he will offend, rather than the location of his base."

That, along with my own deductive reasoning, has inclined me to believe that a relatively confined distribution of murder sites might indicate the likelihood of a perpetrator who commuted to a particular area, with which he had developed a certain degree of familiarity: Having a sense of comfort with its immediate vicinity; but not the sort of comfort and familiarity with the broader surrounding area, that would be expected of a 'local' resident.

That said; I am still of the opinion that the distribution of murder sites, in this case, is mostly a function of the tightly clustered locations of the victims' residences.

...

And once again: If in this day and age, Montague John Druitt were living in Blackheath and practicing in King's Bench Walk, whilst having a particular affinity for Indian Curry; would we be at all surprised to find him spending his free time in Brick Lane? It is entirely possible that Druitt's Indian Curry, in this case, was the sort of 'dolly-mop' that tended to migrate toward that part of London, in which four-penny common lodging houses were most prevalent: Christ Church Spitalfields; but more specifically, the vicinities of Dorset Street and Flower & Dean Street.

To me the major axis of the last and thus far culmative "Deviations from Murder Site Epicenter (Elliptical)" suggests the killer was very comfortable in using the Whitechapel road (or any parallel throughfare closely northward i.e., Wentworth/Montague St.) at least to reach his crime scenes if not to egress from them; ...

The elliptical perspective implies a certain degree of 'mobility' provided by Aldgate High Street / Whitechapel High Street / Whitechapel Road (or as you suggest: Wentworth Street / Old Montague Street); as well as any role that the thoroughfare(s) might have played as 'barriers' in the minds of the victims or killer (or both). This "degree of 'mobility'" may have been specifically 'utilized' by the killer(s); or it may simply have affected the daily routines and activities of the victims, such that each one of them died in an area, in which she was likely to be found.

While I truly believe that the Probability Distribution, which I have depicted, and the 'Geo-Profile' Probability Distribution that I have actually created, both afford invaluable perspectives; I must acknowledge that they may simply be 'profiling' the residences and 'activity spaces' of the victims, while indicating very little about the killer(s).

... further suggesting in my mind that the man was local or at least extremely conversant with the ins and outs of the "Whitechapel Murder District."

Conversely; the directional bias or 'skew' of the murder-site distribution could be indicative of a killer who felt uncomfortable veering too far off of the main 'arteries', for lack of an acute familiarity with the area.

"The elliptical perspective implies a certain degree of 'mobility' provided by Aldgate High Street / Whitechapel High Street / Whitechapel Road (or as you suggest: Wentworth Street / Old Montague Street); …"

I am beginning to favor the notion of "a certain degree of 'mobility' provided by (specifically) … Wentworth Street / Old Montague Street".


Figure 3: Cumulative Probability Distribution (0.00 - 1.00 Standard Deviations) (Circular) (Click to View in flickr)
Underlying Aerial Imagery: Copyright Google Earth, 2007
Overlying Plots, Labels and Color-Shadings: Copyright Colin C. Roberts, 2009


Figure 4: Cumulative Probability Distribution (0.00 - 1.00 Standard Deviations) (Elliptical) (Click to View in flickr)
Underlying Aerial Imagery: Copyright Google Earth, 2007
Overlying Plots, Labels and Color-Shadings: Copyright Colin C. Roberts, 2009

If the crimes are committed within a very small, easily walkable locality, it invariably means that the perpetrator had a base that was centrally located to their criminal activity. In this case, we're talking about a particularly small area, which therefore speaks even less favourably for the commuter hypothesis. The arrival of the "commuter" serial killer has only really been made possible with the advent of readily available private transport, largely unavailable in 1888.

There is not a shred of truth in any portion of the above statement.

As Ben's level of intellect is clearly quite significant; I am inclined to believe that this is a dishonest attempt, on his part, to 'lobby' for the candidacy of George Hutchinson, as 'Jack the Ripper'.


Figure 5: Immediate Vicinity; General Vicinity; Broad Vicinity (Click to View in flickr)
Underlying Aerial Imagery: Copyright Google Earth, 2007
Overlying Plots, Labels and Color-Shadings: Copyright Colin C. Roberts, 2009

"If the crimes are committed within a very small, easily walkable locality, it invariably means that the perpetrator had a base that was centrally located to their criminal activity." (my emphasis)

This is plainly and simply not true; and you would not find a geographic profiler anywhere, to support such a claim.

"In this case, we're talking about a particularly small area, which therefore speaks even less favourably for the commuter hypothesis." (my emphasis (emboldened))

A smaller killing field would speak more favorably for the possibility of a commuter-offender.

"The arrival of the "commuter" serial killer has only really been made possible with the advent of readily available private transport, largely unavailable in 1888."

Charles Lechmere (a.k.a. "Charles Cross") traversed the entire 'killing field' of 'Jack the Ripper' as a matter of daily routine: Doing so on foot. Yet, had he been the killer; he would have been a 'commuter'. The same could be said for literally hundreds (if not thousands) of others, who lived within or just outside the 'General Vicinity' (aqua), but whose daily routines necessitated the traversal of the 'Immediate Vicinity' (red).

"The arrival of the "commuter" serial killer has only really been made possible with the advent of readily available private transport, …", you say? What a JOKE!

My model is based on the very simple premise that at some level of deviation from the epicenter, there exists a '50%-threshold' that determines a level of 'delay' in the cumulative distribution function associated with the six murder sites.

In other words: If we assume, generally speaking, that there is a 50% probability that a doctor will reside within the area, in which he makes house-calls; that there is a 50% probability that a door-to-door salesman will reside within the area, in which he operates; and that there is a 50% probability that a serial-murderer will reside within the area, in which he kills; then that probability will be progressively greater than 50% in the cases of larger areas, and progressively less than 50% in the cases of smaller areas. This would be due to the fact that traversal of an 'area of operations' becomes more difficult as the size of that area increases; thus increasing the likelihood that any 'operator' would be found to be working from within the area itself.

Consider the daily routine of Charles Lechmere (a.k.a. "Charles Cross"), the discoverer of Polly Nichols's body. He traversed the entire 'killing field' of 'Jack the Ripper' each morning, in walking from his home in The Hamlet of Mile End Old Town, to his place of work in The City of London. Clearly, 'Jack the Ripper' could very easily have commuted into his 'area of operations' (from some reasonable distance, of course) on a very regular basis, while possibly traversing the entire area just as regularly.

"… traversal of an 'area of operations' becomes more difficult as the size of that area increases; thus increasing the likelihood that any 'operator' would be found to be working from within the area itself." … i.e. out of necessity. Whereas, traversal of an 'area of operations' becomes less difficult as the size of that area decreases; thus decreasing the 'necessity' for an 'operator' to work from within the area itself.

When one considers the possibility that thousands of 'local' residents, like Charles Lechmere (a.k.a. "Charles Cross"), traversed the entire 'killing field' as a matter of daily routine; ...

………

Rossmo's 'CGT' designates a rectangular 'search area' that is divided into 40,000 'cells'; to each of which a proprietary 'distance-decay' function (including empirically derived constants and exponents) is applied.

My impression is that these functions containing empirically determined parameters will be appropriate (if at all) only to modern cases in which the killer travels over a large area by car, and won't tell us anything at all about a 19th-century case in which he most likely travelled over a small area on foot.

I agree wholeheartedly, Chris! When one considers the possibility that thousands of 'local' residents, like Charles Lechmere (a.k.a. "Charles Cross"), traversed the entire 'killing field' as a matter of daily routine; the application of an extremely complex 'distance-decay' function - utilizing empirically derived constants and exponents - to each of some 40,000 rectangular 'cells', on the basis of just five-or-six data points, smacks of 'milking' what little information we have for infinitely more than it is worth.

And; as I have already stated:

While I truly believe that the Probability Distribution, which I have depicted, and the 'Geo-Profile' Probability Distribution that I have actually created, both afford invaluable perspectives; I must acknowledge that they may simply be 'profiling' the residences and 'activity spaces' of the victims, while indicating very little about the killer(s).

… the point I was making is a rather different one.

The profilers are using complicated functions that depend on empirically determined parameters. But even if one assumes the approach is valid, there is no reason to think the parameters that have been determined for 20th-century murderers travelling by car are the same ones that would apply to a 19th-century murderer travelling on foot. So even in their own terms, in applying their computer models to the Whitechapel Murders they are probably using the wrong parameters, and therefore getting the wrong probability distribution.

I see your point, Chris; and I certainly concur.

The utilization of empirically derived parameters imposes a 'twentieth-century perspective' upon what ought to be a 'nineteenth-century solution'.

As an 'aside':

"If the area covered by a series of crimes is circumscribed, then in the majority of cases the serial offender has a base of some sort within that area. Let me hasten to add that this is not true in all cases, and the proportion of offenders who live within this 'criminal range' varies considerably depending on many aspects of the crimes and locations. But as a rule of thumb there is at least a 50-50 chance that the offender lives within the area defined by a circle that joins the two furthest crimes. If the spread of the crime is great and the criminal thinks he may be recognized in a given location then the chance he lives within this circle increases. If the criminal is clearly targeting a particular type of criminal opportunity then the chance will decrease because it is the opportunity for the crime that determines where he will offend, rather than the location of his base. There is thus the real possibility that Jack came into the area because of the opportunities available to carry out his mission. But the distribution of the crimes around the small area, together with their timing, also offers the possibility that he had a base in the area."David Canter, Mapping Murder, p. 131.

"But as a rule of thumb there is at least a 50-50 chance that the offender lives within the area defined by a circle that joins the two furthest crimes."

There are in fact, several practical methods of 'defining' a 'killing field':

- Smallest Circle of Enclosure (as mentioned by Canter)

- Smallest Rectangle of Enclosure

- Smallest Convex Polygon of Enclosure (Convex Hull) (i.e. a 'connection of the dots': from Chapman to Nichols; to Stride; to Eddowes; to Kelly; to Chapman) (Tabram is bypassed in order to maintain convexity)

- And; My Preferred Methods …


Figure 6: Cumulative Probability Distribution (Greatest Deviation: Nichols) (Circular) (Click to View in flickr)
Underlying Aerial Imagery: Copyright Google Earth, 2007
Overlying Plots, Labels and Color-Shadings: Copyright Colin C. Roberts, 2009


Figure 7: Cumulative Probability Distribution (Greatest Deviation: Nichols) (Elliptical) (Click to View in flickr)
Underlying Aerial Imagery: Copyright Google Earth, 2007
Overlying Plots, Labels and Color-Shadings: Copyright Colin C. Roberts, 2009

In this particular instance (i.e. in the case of 'Jack the Ripper') the 'Smallest Circle of Enclosure' seems quite practical. …


Figure 8: Cumulative Probability Distribution (Greatest Deviation: Nichols) (Circular) / Smallest Circle of 'Enclosure' (Click to View in flickr)
Underlying Aerial Imagery: Copyright Google Earth, 2007
Overlying Plots, Labels and Color-Shadings: Copyright Colin C. Roberts, 2009


Figure 9: Cumulative Probability Distribution (Greatest Deviation: Nichols) (Elliptical) / Smallest Circle of 'Enclosure' (Click to View in flickr)
Underlying Aerial Imagery: Copyright Google Earth, 2007
Overlying Plots, Labels and Color-Shadings: Copyright Colin C. Roberts, 2009


Figure 10: Cumulative 'Geo-Profile' Probability Distribution (0.00% - 50.00%) (Circular) (Click to View in flickr)
Underlying Aerial Imagery: Copyright Google Earth, 2007
Overlying Plots, Labels and Color-Shadings: Copyright Colin C. Roberts, 2009


Figure 11: Cumulative 'Geo-Profile' Probability Distribution (0.00% - 50.00%) (Circular) / Smallest Circle of 'Enclosure' (Click to View in flickr)
Underlying Aerial Imagery: Copyright Google Earth, 2007
Overlying Plots, Labels and Color-Shadings: Copyright Colin C. Roberts, 2009

… However, its derivation (in other instances) might not be as straight-forward as Canter would have us believe.

"… the area defined by a circle that joins the two furthest crimes."


Figure 12: Smallest Circle of 'Enclosure' ??? (Click to View in flickr)
Underlying Aerial Imagery: Copyright Google Earth, 2007
Overlying Plots, Labels and Color-Shadings: Copyright Colin C. Roberts, 2009

Believe It; Or Not: Each of the hypothetical murder-sites (yellow) is in closer proximity to both the Eddowes and Nichols murder-sites; than are the Eddowes and Nichols murder-sites, to each other.

Quite frankly: I wouldn't know how to draw a 'Smallest Circle of Enclosure' for this hypothetical distribution of murder-sites.

Finally: If I am going to begin the process of a formal presentation of my Geo-Spatial Analysis project, which should hopefully answer most of your questions, and alleviate a great deal of your confusion regarding my informal presentations to date; then I must excuse myself from further participation in this thread. In other words: Things aren't materializing as they should; and so, I must 'get to work'.

[JRJ]

Wentworth Street / Old Montague Street

Colin,

You now seem to support my suspicion that the WM used Wentworth Street / Old Montague Street as his main artery:

I am beginning to favor the notion of "a certain degree of 'mobility' provided by (specifically) … Wentworth Street / Old Montague Street"

I’m curious as to why you have begun to swing your views in this direction.

My reasoning is as follows.

1) The Geo Profile centers on Wentworth Street / Old Montague Street
2) The Geo Profile centers north of Whitechapel Road, and if one eliminates the Stride Murder, the center gets shifted even further north away from Whitechapel Road.
3) The twists, turns and byways of Wentworth Street / Old Montague Street would have made it easier for the WM to travel unnoticed and unfollowed.
4) This last is a supposition albeit, perhaps not an unreasonable one (if not I’d appreciate if someone would disabuse me of this impression); the prostitutes would not have regularly paraded themselves on a main thoroughfare like Whitechapel Road, (These unseemly vagrants getting shushed to sidestreets and the ‘red light’ districts by patrolling constables.) So the WM would have done his hunting where his prey travelled.

I’d also like to add that while Colin’s profile does not prove that the WM was a local man, in my view his apparent familiarity with its byways increases its likelihood.

JRJ

[Ben]

There is not a shred of truth in any portion of the above statement.

As Ben's level of intellect is clearly quite significant; I am inclined to believe that this is a dishonest attempt, on his part, to 'lobby' for the candidacy of George Hutchinson, as 'Jack the Ripper'

Which is a shoddy, disgraceful accusation for you to make. Ludicrously illogical, and if you accused me of dishonesty to my face, I'd probably be physically violent. It has nothing whatsoever to do with George Hutchinson. It has to do with what has been learned from studies into serial killers.

This is plainly and simply not true; and you would not find a geographic profiler anywhere, to support such a claim.

Really? Well then why does one of the pioneers of geographical profiling express the view that he lived in the heart of the murder district? Why didn't he suggest that he was a commuter who waltzed into the murder district from outside? Flower and Dean Street is pretty central to the base of operations, and no, George fcuking Hutchinson didn't live there. Or is this the latest in another mind-bogglingly crass attempt to invalidate the expert's opinion on the subject? There is little to no evidence of serial killers who commute from a distance, continually, into a tiny pocket of a particular circumscribed locality which they keep visiting to murder and dispatch victims despite the increased police presence. Colin Ireland may have picked up his victims in a particular locality, but he murdered them elsewhere, because that was made available by greater transport availability.

By "commuter" I refer to those who journeyed to the crime scenes from an appreciable distance away. If the killer lived in the areas shaded turquoise or even purple, he would still be regarded as a locally-based offender.

I would happily have complimented you on your research efforts, but if you're going to make such nauseating attacks on my integrity, I don't think I'll bother. I'm sick of being accused of having nefarious reasons for expressing a particular view, and I'm sick of being attacked for responding with justified anger when it happens.

Sorry about that, everyone.

Now, back on topic, unless people want to continue the hostilities.