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**Guest** · 04-12-2022, 11:55 PM

Here's mine.

Prior Knowledge of Whitechapel Area — 100%

Without a doubt. He was almost caught on the night of the double homicide. The only way he could have escaped and melted into the night so easily would be a familiarity with the area.

Suspected By Named Police on the Ground — N/A

I cannot comment on this as I have no idea what the structure of law is like in the UK. In the US, there are constitutional protections written in stone and they affect the way suspects can be interviewed, compelled to provide evidence, etc. I assume the UK has some, too, but I know they're different than ours and I can't imagine what it was like 130 years ago outside of my country.

Anatomical Knowledge — 98%

I know that Ripper had anatomical knowledge for a fact because my mother has been a surgical RN for the past 46 years and I have knowledge of anatomy myself, but I put my rating at 98% to indicate that I am still unsure what his profession actually was. I haven't read the autopsy reports and I don't know if he simply cut organs out or if he carefully excised them. The former would lead me to a belief that he was a taxidermist, furrier, or butcher while the latter would lead me to think he was a doctor.

Exhibiting Obvious Signs of Mental Illness — 0.5%

I am a mental health patient. I have Obsessive Compulsive Disorder, Attention Deficit Disorder, Generalized Anxiety Disorder, and Major Depressive Disorder and, as previously mentioned, my mother is an RN. I have an understanding of PET scans and I can tell you that a psychopath's brain actually features less activity in the prefrontal cortex, which controls planning complex cognitive behavior, personality expression, decision making, and moderating social behavior, than is seen in normal, outgoing and friendly people. In other words, when you get angry at your sister and you feel like you could just choke her, the prefrontal cortex is the part of your brain that says "Uh, no. We are not about to end up on Discovery ID!" Horrifyingly, the psychopath doesn't have this little inner monologue at all. They have no inhibitions and they have no remorse. One would think that a lesser amount of activity in this part of the brain would affect a murderer's ability to plan complex crimes, but when psychopathy is coupled with a high intelligence (which we can assume Ripper had by Victorian standards based on the aforementioned knowledge of anatomy in an era where many were entirely illiterate), you end up with a brain that can "think on its feet" and be three steps ahead of others in any given plan plus the lack of inhibitions, empathy, and remorse. Intelligent psychopaths also possess an extraordinary ability to compartmentalize and this coupled with their cunning affords them the ability to appear perfectly kind, happy, and normal. I give this one a 0.5% because I am almost entirely certain that Ripper was a psychopath, but until we know who he is, we can never determine that.

Prior Criminal Acts — 99.5%

This one is 99.5% for the same reason as the above is 0.5%, only in the opposite direction. We can never know for certain until we know who Ripper is, but there is almost always a period of escalation in serial murderers.

Suspect Turns Up in Police Reports on the Whitechapel Murders — N/A

For this one, I'm not really sure because I have no knowledge of English law when it comes to who the police are allowed to question, how long they can be held, etc. I know that in today's United States, it has long since been standard practice to fingerprint every suspect that is brought into the station and they are uploaded to a system called AFIS (Automated Fingerprint Identification System), where they are checked against a database of thousands of arrest reports for a match on any priors, which they end up finding on most suspects. However, I could never speculate as to British police procedures before the world of forensics. The idea that each person had a different set of fingerprints was a wild theory with only a few subscribers in 1888.

Able to Put Victims at Ease — 95%

For this one, I selected 95% because if Ripper was a psychopath, then there is absolutely no doubt, but I agree with you that even a middle-class man in a halfway decent suit would appear attractive and trustworthy to prostitutes who were struggling to earn 4 pence for a bed.

Lived Locally — 20%

My assessment on this one is based on the understanding that modern-day serial killers often stalk their victims for weeks ahead of time or, at the very least, familiarize themselves with the grounds where they intend to kill. A person does not need to live in an area to know its layout and if Ripper was an intelligent psychopath, which is likely, then he would have planned ahead. That said, I would rate an assumption that he worked in the area at closer to 80%.

Knew His Victims — 5%

I really doubt that Ripper knew his victims as well as he did the location. I can see how he might have recognized a pretty face in the crowd, but in my opinion, it's more likely that he knew where he wanted to kill and then took whichever woman was convenient in that area.

Caught / Apprehended — 5%

For this one, it is clear that the crimes stopped after Mary Kelly, but that in no way indicates to me that Ripper stopped killing entirely. In the United States, for example, it wasn't until almost 80 years later that police started collaborating across jurisdictions instead of handing off cases to whichever one the crime belonged to. In 1888, without the modern convenience of forensic science to detect invisible traces of a person, I'd say that it was highly likely that Ripper just moved on to a new area and continued to kill, especially if he was a psychopath who was mentally three steps ahead at all times.

**Hakeswill** · 04-13-2022, 10:04 PM

Hello and thank you for your thoughts.

Straight away you've made me reconsider some things in light of your comments. I would go so far as to say that the only completely known facts are that there were several murders committed on known dates, say the C5 (maybe MT too), but I couldn't even say with 100 % certainty that MJK was identified correctly. I'd put the likelihood at 95 % for four and maybe 90 % for all JTR being the perpetrator on all 5, just trying to account for reasonable doubt.

1 This is more about cutting out some of the more exotic suspect suggestions. I'd strongly suspect he lived and worked in the area.
2 Possibly the strongest suspect 'evidence' comes from police suggestions, like Kosminski, Druitt, Ostrog, Chapman. I know a lot of the original notes are lost but I think its more likely than not that JTR's name was at least once somewhere in notes that could still exist. I am aware of several more modern cases for example where a suspect is essentially known but the name doesn't come out due to lack of the necessary evidence to convict, so I do put more stock by the named suspects than others.
3 Agreed. Dr Phillips thought so, Dr Bond disagreed but only saw MJK.
4 Very poor wording on my part. I wrote it this way since several officials connected to the case made remarks such as 'homicidal and erotic mania', 'lunatic' or 'engaging in solitary vices' and are very much descriptions of their time. A modern policing view would certainly not look at things in the same way. There are also multiple suggestions that suspects were placed in asylums at some point, sometimes by families. Whilst I think it is nearly 100 % certain that JTR would have at least one diagnosable mental health condition that could be related to his crimes, I don't think it would necessarily show up in a recognisable way, so I revise my original estimate down to 15 %
5 Fair enough
6 As point 2
7 Fair enough, I just don't see JTR as a Ted Bundy charming type. Maybe just didn't look threatening. Could be completely wrong with that.
8 As number 1
9 Knew personally, I think no. But plausible that he would have seen/recognised some I think just due to size of the area involved and I think it plausible that he was familiar with the locations where the sex workers would go by habit.
10 Yeah, I find this an awkward one. Personally, since I think JTR was working class and lived locally, I find it more difficult to accept he could just get up and move to another location when the heat got too much (unless he worked in something related to sailing, of course). If he did move away, I would also find it less likely that he would then simply be able to stop his actions. In more modern cases where a killer has stopped (say De Salvo or BTK) they weren't the same type of killings. Analogues that spring to mind for me would be killers like Gary Ridgeway or Robert Napper. Maybe this category needs to be better defined rather than 'caught'.

H

**Guest** · 04-14-2022, 12:09 AM

As to #1, #8, and #10, I am intrigued by the Carrie Brown murder in New York in 1891. My favorite suspect is H.H. Holmes, who was constantly on the move because he was running so many financial scams that he couldn't stay in one place for very long. There were so many scams, lawsuits, and fraudulent activities that he can be placed by a document of some sort, based on where it was issued and when it was dated, for the entire period of his adulthood and there is an unusual gap in American activities during the time of the Whitechapel murders and his known aliases were also found on passenger manifests heading to and from England at around the same time. I don't want to be biased, though, so I'm definitely going to be examining the autopsy reports on Carrie Brown to find out if any organs were taken, etc. I know that there was a theory at the time that Ripper was collecting the organs to sell to medical schools and it is well known that in America, the purpose of H.H. Holmes' "Murder Castle" was to somewhat industrialize his murders and make them more efficient because he was killing people, cleaning them, and then re-articulating their skeletons to sell to medical schools as one of his financial hustles. There's a new video game coming out that is going to feature a replica of the Murder Castle which one has to escape from, so I'm looking forward to learning more about the structure itself and also learning what specific organs other than skeletons that Holmes was selling.

**JeffHamm** · 04-16-2022, 12:54 AM

Inferential statistics, which is what you're talking about with regards to things like Bayesian, can be a very useful tool with regards to evaluating ideas based upon evidence, provided of course the evidence is quantifiable (can be represented by numbers).

The idea of Bayesian statistics, short version, is that you have some bit of evidence, and you have two, or more, explanations (theories) for how the world is. Bayesian statistics takes the evidence you have and tries to work out the odds ratio that your observed evidence would arise from theory A compared to theory B (I'll leave it at two theories for simplicity). Basically, you end up with something like this evidence is 10 times more likely to arise if theory A is true than if theory B is true.

The downside of Bayesian statistics is that while your evidence may be more likely to come from theory A than theory B, it says nothing about whether or not the evidence actually matches what theory A predicts the evidence should have been! For example, let's say theory A predicts you should observe a value like 75, and theory B predicts you should observe the value 10. You end up measuring a value of 200. That is far more likely to arise from theory A than theory B, so Bayesian statistics would support Theory strongly, despite the fact the evidence is very different from what Theory A actually predicts! For some reason, many people think that Bayesian statistics is about evaluating if a theory is true in the absolute sense, it's not. It is just indicating which of the theories better accounts for the observed data, but it says nothing about how accurate the theory is (and a true theory should not just be more probable to produce the evidence, but also produce accurate predictions).

Null hypothesis significance testing (NHST), on the other hand, tests whether or not the "null hypothesis" produces accurate predictions (the null hypothesis is generally things like "there's no effect of my manipulation", but there's no reason why one can test against a theory's predicted value. For example, I could use a NHST to see if my evidence is what Theory A predicts, and let's say I find that 200 (my observed value) is found to differ from 75 (Theory A's prediction), then I would conclude that Theory has something wrong with it because it makes inaccurate predictions. I would find the same for Theory B, which predicted a value of 10.

The problem most people have with NHST is that when you do not find that the predicted values are inaccurate (referred to as a nonsignficant finding - and not an "insignificant" finding), you cannot present that as evidence the theory is true (that's called accepting the null). That's because NHST is not testing if the theory is true, rather, it is testing if the predictions it makes are accurate. It might have accurately predicted your observation, but still be false. At issue is there is a history of statistics being taught, and phrased, as a significant NHST indicates the theory is false when it should be phrased as NHST indicates the predictions are inaccurate. If thought of in that way, then it would be entirely acceptable to present a nonsignificant finding as indicating the predictions were accurate, and then one couples that with a Bayesian evaluation, and can also say that Theory A is 10 times more likely to produce the finding than theory B.

With my original presentation, though, we might end up with While neither theory produces an accurate prediction, the observed values are 10 times more likely to have been generated by Theory A than Theory B; meaning the evidence is more supportive of Theory A than B, but Theory A itself still needs work.

Anyway, that aside (and I hope everyone is still awake), let's consider just one of the ideas you've presented, the notion that the offender is familiar with the area. Canter and Larkin offered what they called the home range hypothesis with regards to criminal choice of locations, and which is one of the major theories behind geographical profiling. Basically, they described the "home range" as the collections of locations that people frequently end up in during their every day lives, so their residence, their place of work, clubs, pubs, places of worship, the grocery store they shop at, and so forth. Offenders also have their criminal range, and that's the area in which they are willing to offend. Now, how an offender chooses a location to offend is not random; even a "crime of opportunity" is not entirely random because the offender still has to decide that the opportunity is worth acting upon and that requires a decision of some sort. Anyway, they suggested two possible approaches to offense location choice that might underlie the decision process. First, what is called the "marauder" decision model, offenders will choose locations based upon becoming familiar with locations during their every day life. Basically, they spot opportunities as they go about their daily life. This allows them to offend in areas they are very familiar with, lowering the perceived risk, and also allowing them to have a ready to hand excuse for being in the area. The alternative is that offenders do not want to offend where they might be recognized, and so they avoid the areas they associate with normally, and travel to another location in order to offend. This would be the commuter model and it offers a different way one might choose to reduce associated risk (if you are spotted you are less likely to be recognized vs a marauder, where you know the area and it's "habits" and can explain your presence, etc).

So, what Canter and Larkin proposed was that you first encompassed the offense locations with the smallest possible circle that contains them and we'll call that the criminal range. It's a simple estimation of the area in which the offender is willing to offend. Now, if more offenders choose those locations based upon a marauder type decision scheme, then there will be a large amount of overlap between the criminal range and the home range of the offender. The home range being the circle that encompasses their daily life "anchor points" (residence, work, etc). They also argued that one's residence will be one of the more influential anchor points, and so they said the marauder model predicts the offender will tend to live inside the criminal range. The commuter model, of course, predicts the criminal range will be distant from the offender's daily routines, and so predicts offenders will not live inside the criminal range.

Years of research into the pattern of serial offenders has generally shown that in the vicinity of 80% of offenders do indeed live inside the criminal range, indicating that the majority of offenders seem to follow a marauder decision making pattern.

I have just had a publication accepted, where I examine this in a lot of detail. What I show is that the shorter the crime series the more (on average) the criminal range defined by the observed offense locations underestimates the true size of the area the offender is actually willing to offend in. I suggest a way to compensate for this (basically, make the criminal range circle bigger for shorter series), and also point out that just because an offender lives outside the offense areas doesn't mean they are a commuter if, for example, they work inside it. That would just mean for that offender the main anchor point they are operating around isn't their residence (Dennis Rader, for example, appears to be more strongly tied to his work location than his residence location when it came to the locations he offended). In the end, I suggest that the percentage of offenders operating on a commuter type decision model is probably very small, and so the article is titled "They might all be marauders" (note the use of "might" is intentional, it's not a claim that all offenders any and everywhere are marauders, only that a researcher has to consider the possibility that all of their offenders in their data sets are marauders). True commuters are probably only happening if the offender is transient, and moving from location to location and so offending as they pass through an area. But then one wouldn't get a cluster of 5 murders all in the same general area, but rather a much more widely distributed set of locations in different towns, or at least different parts of London.

Geographical profiling routines, get a bit more involved than just drawing a circle, of course, but they are based upon the idea that the home range and criminal range overlap, and so are trying to refine things to highlight areas of greater probability as the "circle" method just says "in here somewhere". The circles can be many hundreds or thousands of square km, so really, that isn't a great deal of help.

As such, there is a very high probability that JtR is also a marauder, though of course it is not guaranteed. And by that I just mean he has some connection with the area. It may be he lives there (within a circle a bit bigger than that which encloses all the crime locations), or works there, or he lives nearby and goes to the pubs there, type thing. Given more of the offenses are north of Whitechapel road, it's more likely his anchor point is north of Whitechapel as well.

But unless he ever gets identified, well, we can't compare his data with the predictions! We can evaluate different suspects, for example, but in the end, many individuals will have had an association with Whitechapel so just because someone fits the predictions doesn't mean they're JtR. Remember, the hypothesis is that "JtR will fit the predictions", and not that "only JtR will fit the predictions" - remembering that it is not "only JtR" that might fit the predictions is very important, and often gets overlooked.

- Jeff

**GBinOz** · 04-16-2022, 01:19 PM

Hi Jeff,

Thanks for the informative post. I think I understood some of it. If we look at some of the popular persons of interest here at the moment, without any endorsement of candidature for the title of JtR, would Druitt and Lechmere fall into the Commuter category? I recall another theory that the first victim of Commuters is usually the closest to their home. This would not seem to apply to Druitt but could apply to Lechmere, depending on one's view of the candidacy of Tabram as a JtR victim.

Best regards, George

**Aethelwulf** · 04-16-2022, 03:16 PM

Originally posted by GBinOz View Post

Hi Jeff,

Thanks for the informative post. I think I understood some of it. If we look at some of the popular persons of interest here at the moment, without any endorsement of candidature for the title of JtR, would Druitt and Lechmere fall into the Commuter category? I recall another theory that the first victim of Commuters is usually the closest to their home. This would not seem to apply to Druitt but could apply to Lechmere, depending on one's view of the candidacy of Tabram as a JtR victim.

Best regards, George

Also Bury - Wilson, 1 mile from his lodgings in Bow. The fact that she survived could explain why there were no other attacks close to his home.

**JeffHamm** · 04-16-2022, 08:55 PM

Originally posted by GBinOz View Post

Hi Jeff,

Thanks for the informative post. I think I understood some of it. If we look at some of the popular persons of interest here at the moment, without any endorsement of candidature for the title of JtR, would Druitt and Lechmere fall into the Commuter category? I recall another theory that the first victim of Commuters is usually the closest to their home. This would not seem to apply to Druitt but could apply to Lechmere, depending on one's view of the candidacy of Tabram as a JtR victim.

Best regards, George

Hi George,

Druitt had a relative, I believe (cousin or something), who had a medical office or something in the area. While there is nothing to show that Druitt himself spent time there, etc, that would be something the police of today might investigate if Druitt had come up on their radar (and maybe they did when he became of interest to them but that information is lost to us). If MJD did have some connections to that location, say he was close to that relative and they often met up there, etc, then that would create an anchor point for Druitt's daily life (home range) that ties him to the crime range. And that location isn't all that far from Tabram's murder location. However, if he wasn't associated with that location, then I think his own office is far enough away that Druitt would have to be considered a commuter. Also, the direction of flight from Eddowes' crime, based upon the location of the apron, is away from either of those proposed "bolt holes".

As for Lechmere, his residence is on one side of the crime range and his work on the other, so the crime range entirely overlaps his home range based on those two locations alone, add in his mother's residence, and his previous residence, and the overlap is even more apparent. That would would mean he would be considered a marauder.

But remember, there will be many many many people who have home ranges that overlap with the crime range. Think Pizer, or Kosminski, Paul, Hutchinson, Barnett, and so forth. These types of analysis suggest where to look, not who to look for! It's sort of the opposite side of the coin to listing all the people associated with victim (spouse, family, friends, co-workers, etc) - those prioritize "who to look at" rather than "where to find them". Spatial analysis is about prioritizing "where to look" rather than "who to look at".

- Jeff

**JeffHamm** · 04-16-2022, 09:07 PM

Originally posted by Aethelwulf View Post

Also Bury - Wilson, 1 mile from his lodgings in Bow. The fact that she survived could explain why there were no other attacks close to his home.

Hi Aethelsulf,

If Bury had locations he was known to frequent in the Whitechapel area, say a pub, or mistress, etc, then that would turn him into a marauder. One of the issues that has slowed things down in this area is the over emphasis on the residence location beyond what it deserves. Yes, it is a strong anchor point, and very often does fall within the crime range, but not always. And just because an offender's residence is not in the crime range that alone does not rule them out as a marauder. Anchor points include work, pubs, relative's locations, and other locations a person is known to frequent with some regularity.

But again, I cannot emphasize enough, spatial analysis is about determining where in space to look, not who to look for per se. There will be many many many people with anchor points in the suggested area. Investigators are simply advised that, if you don't have leads to follow up, then look here as this area may be more likely to provide results than this other area over here. It's not evidence for or against a person on its own - it suggests a search strategy to find information, it is not the end result of that search.

It is also a probabilistic suggestion, and low probability events do sometimes happen, so one should never decide to stop investigating someone for whom there is evidence suggesting they are worth looking at simply because they don't fit the spatial analysis.

- Jeff

**Aethelwulf** · 04-17-2022, 06:39 AM

Originally posted by JeffHamm View Post

Hi Aethelsulf,

If Bury had locations he was known to frequent in the Whitechapel area, say a pub, or mistress, etc, then that would turn him into a marauder. One of the issues that has slowed things down in this area is the over emphasis on the residence location beyond what it deserves. Yes, it is a strong anchor point, and very often does fall within the crime range, but not always. And just because an offender's residence is not in the crime range that alone does not rule them out as a marauder. Anchor points include work, pubs, relative's locations, and other locations a person is known to frequent with some regularity.

But again, I cannot emphasize enough, spatial analysis is about determining where in space to look, not who to look for per se. There will be many many many people with anchor points in the suggested area. Investigators are simply advised that, if you don't have leads to follow up, then look here as this area may be more likely to provide results than this other area over here. It's not evidence for or against a person on its own - it suggests a search strategy to find information, it is not the end result of that search.

It is also a probabilistic suggestion, and low probability events do sometimes happen, so one should never decide to stop investigating someone for whom there is evidence suggesting they are worth looking at simply because they don't fit the spatial analysis.

- Jeff

Good post as usual Jeff.

What people seem to forget about proposing Bury as a possible candidate for the Wilson attack is what the attack involved in relation to the written evidence of Bury’s habits and nature. It sounds like Wilson’s attacker wanted money and then stabbed her in the throat in a fit of rage (I think Tabram was also stabbed in the throat?). There is also a suggestion that Wilson’s occupation as a seamstress meant prostitute (cannot remember where I read that but think it was on here somewhere).

The written evidence suggests that Bury’s beatings of his wife were money related, either him wanting money or Ellen trying to pay back money he owed. So there is a similar money element. Ellen also found that Bury was sleeping with a penknife under his pillow. At his arrest he owned a two bladed penknife and a clasp knife. We also know Bury could react violently without provocation (e.g., the example I’ve cited previously of Ellen being out looking for Bury, he sees her, asks her she is doing here, and punches her three times until she collapses). Bear in mind when he did that he most likely had that penknife he was keeping under his pillow in his pocket – what would he do to a stranger that provoked him? Finally, Bury caught an STD in spring 1888 and gave it to his wife, so he was likely using prostitutes. Ellen was a prostitute as well. Bury’s use of prostitutes could be a reason he was in Wilson’s area of town. Add in the close location to Bury's home and it is far from unreasonable to suggest Bury for this.

Given there were other penknife attacks early in the potential JtR series (obviously disputed), and Bury can be placed as drunk in Whitechapel, so we know he went there, he used prostitutes and has displayed rage, and rage seems evident in the Tabram attack. We also know there is a very good match to the FBI profile of the killer, we know what he did in Dundee. I just think if you go through each suspect objectively, look at the pros and cons of each, I can’t help but have Bury top of the pile.

Two things I would like to know in relation to Bury and the geoprofile, but are unknowable I suspect: Bury's favourite pub in whitechapel and where he stabled his horse.

**NotBlamedForNothing** · 04-17-2022, 08:16 AM

Originally posted by Hakeswill View Post

7 Able to put victims at ease 60 %

Revised this down. In more recent homicide cases involving sex workers, the need they had for money meant they had to out themselves in to more dangerous situations. Assuming he wasn't raving and screaming, I don't think he would have to have been particularly convincing in his chatter

I don't understand why so much weight is often put on this one. What were all the other punters doing that Autumn? Did they all quickly learn to put the ladies at ease? Or did the ladies start turning down punters in large numbers, given all those who had not learnt that required skill?

This makes me wonder about the broad-shouldered man. Did he fail to put the lady at ease, and then after having been rejected, proceed to kill her with all the skills of Jack the Ripper?

**JeffHamm** · 04-17-2022, 09:14 PM

Originally posted by Aethelwulf View Post

Good post as usual Jeff.

What people seem to forget about proposing Bury as a possible candidate for the Wilson attack is what the attack involved in relation to the written evidence of Bury’s habits and nature. It sounds like Wilson’s attacker wanted money and then stabbed her in the throat in a fit of rage (I think Tabram was also stabbed in the throat?). There is also a suggestion that Wilson’s occupation as a seamstress meant prostitute (cannot remember where I read that but think it was on here somewhere).

The written evidence suggests that Bury’s beatings of his wife were money related, either him wanting money or Ellen trying to pay back money he owed. So there is a similar money element. Ellen also found that Bury was sleeping with a penknife under his pillow. At his arrest he owned a two bladed penknife and a clasp knife. We also know Bury could react violently without provocation (e.g., the example I’ve cited previously of Ellen being out looking for Bury, he sees her, asks her she is doing here, and punches her three times until she collapses). Bear in mind when he did that he most likely had that penknife he was keeping under his pillow in his pocket – what would he do to a stranger that provoked him? Finally, Bury caught an STD in spring 1888 and gave it to his wife, so he was likely using prostitutes. Ellen was a prostitute as well. Bury’s use of prostitutes could be a reason he was in Wilson’s area of town. Add in the close location to Bury's home and it is far from unreasonable to suggest Bury for this.

Given there were other penknife attacks early in the potential JtR series (obviously disputed), and Bury can be placed as drunk in Whitechapel, so we know he went there, he used prostitutes and has displayed rage, and rage seems evident in the Tabram attack. We also know there is a very good match to the FBI profile of the killer, we know what he did in Dundee. I just think if you go through each suspect objectively, look at the pros and cons of each, I can’t help but have Bury top of the pile.

Two things I would like to know in relation to Bury and the geoprofile, but are unknowable I suspect: Bury's favourite pub in whitechapel and where he stabled his horse.

Hi Aethelwolf,

One has to be careful in how they deal with linkage, meaning which crimes are part of the series. One has to avoid the temptation of linking an offense because it fits a particular suspect as that is working backwards. Linkage analysis has to be based upon aspects of the offenses themselves, without reference to any particular suspect, even a "theoretical one". An example of the latter, and how it creates problems, is the Yorkshire Ripper case. The police had a theoretical suspect, one who specifically targeted prostitutes. As a result, they failed to link attacks on women who were not prostitutes, going so far as to suggest one attack that was so clearly similar to the others but where the victim was not a prostitute but a young girl of around 16 was a mistake by the offender rather than a mistake on their part. It became even worse when they accepted without question letters and later recordings sent to them as genuinely being from the offender, redirecting their search away from local suspects. In this example, of course, the problem was a failure to properly link cases rather than including offenses committed by others, but both types of errors skew the evidence one has to explain.

So, for the non-C5 murders and attacks, one needs to argue for their inclusion or exclusion solely on the basis of the offenses themselves, and not be influenced (if that's even possible) by knowledge of their preferred suspect. Otherwise, one may include offenses because they bring the series closer to where their suspect is known to be located, or they exclude cases because their suspect is known to be unable to have committed them.

So when it comes right down to it, Wilson was stabbed, with a pen knife during what appears to be a robbery, and the offense occurred in doors. There was no attempt at initial silencing of her, and the offender, after injuring her, fled the scene immediately, and so forth. Obviously there's more details and ideas involved in just those, and discussions about her attacks do focus on those points, calling some into question, and so forth, but those are the points to focus on. To what degree of certainty, based upon the offense itself, can one state she was or was not attacked by the same offender who attacked the C5. Linkage analysis must always precede suspect evaluation, one should avoid as best they can considering their suspect during the process of linkage analysis. After all, if one's preferred suspect is indeed the offender for the C5 it becomes immaterial if some other victim is or is not include - one is interested in which offenses that person committed, not increasing a longer or shorter list of victims.

Admittedly, things change if someone has been proven to be responsible for a given series of crimes, at which point other unsolved offenses might then be compared with that known offender to see if perhaps they were responsible for them. That's a bit different because now that person has been proven to have committed a series of offenses so the unsolved cases are not being evaluated in order to prove the suspect was involved in the series (that's been done), but rather to then re-evaluate what was the extent of their series.

Basically, there is a sort of back and forth between the bits of information we have. Of the non-C5 cases, I tend to think Tabram and McKenzie are the two that deserve the most focus when it comes to discussion of possible inclusions, and of course Stride is the C5 for whom there is the most doubt about her inclusion. I don't think any real consensus will be arrived at for any of those 3 separate cases, of course. The implication if Tabram were decided to be included is that it opens up arguments for pretty much any knife crime against a woman, even if less brutal, because it was earlier. And if McKenzie were to be included and Stride retained, then the apparent reduction in the mutilation severity allows for inclusion of other cases where mutilations were not performed. In other words, the information we have that provides for strong linkage between Nichols, Chapman, Eddowes, and Kelly (the C4) starts to get watered down to the point where one could argue for any attack upon a woman, and so one is more likely to include cases by multiple offenders.

Generally, though, if one focuses on the C5, and keeps an open mind about other possible offences, then the idea is that identify the person responsible for the C4 and then go back and look at the other possible cases and see if that person can be linked to them; but it would take something solid evidence wise to connect them to an additional offense. Obviously, if one could solve one of the "reserve cases", then again one might want to see if that person can be linked to the JtR series, but again, it requires something solid evidence wise, not simply "well, they lived in the area" or "we don't know where they were so they might have been there", etc. All those do is leave them open to investigation and consideration, they don't show their involvement.

As such, Bury is certainly worth including as a suspect. And it would be interesting to know more details about his habits and whereabouts, but that of course applies to all the suspects. Generally, the geoprofiles of the C5 point up around the Kelly/Chapman area as the main focus, and radiate out from there along Commercial down towards Whitechapel. Hutchinson and Barnett, as I recall, are two proposed suspects who resided closest to the area of interest. However, there are a lot of pubs in that area, and if the anchor point that is being focused upon is not the offender's residence but the pub or pubs they tended to frequent, then it becomes apparent just how many individuals we're talking about. This is why spatial analysis is not evidence in and of itself, rather it is a tool that provides a suggestion of where to look for evidence.

- Jeff

**GBinOz** · 04-18-2022, 01:47 AM

Hi Jeff,

The problem with this type of mapping, as I see it, is choosing which victims to include in the group. The early contention was that Smith, Tabram and Nichols formed a group, but a map using those three examples would not contain any of the following murders. The Whitechapel Murders + The Thames Torso Murders amounts to 14 in total. The C5 seems to be an arbitrary group rationalised after the events and disputed to this day. But unless it is accepted that all 14 murders were by the same hand, we have to accept that there are two or more individuals involved, and it then follows, how many individuals, and which victims to attribute to which individual. A quick glance at the map below would seem to place Nichols as an outlier, and her inclusion in any group would have a marked effect on the shape of the resultant map compared to map that excludes her. Likewise, the inclusion/exclusion of any victim would have a marked effect on any result, as would increasing/decreasing the number on perpetrators.

I suppose that I am just wondering as to how useful a map prepared using modern scientific analysis can be when the input data is so uncertain?

Best regards, George

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**JeffHamm** · 04-18-2022, 03:05 AM

Originally posted by GBinOz View Post

Hi Jeff,

The problem with this type of mapping, as I see it, is choosing which victims to include in the group. The early contention was that Smith, Tabram and Nichols formed a group, but a map using those three examples would not contain any of the following murders. The Whitechapel Murders + The Thames Torso Murders amounts to 14 in total. The C5 seems to be an arbitrary group rationalised after the events and disputed to this day. But unless it is accepted that all 14 murders were by the same hand, we have to accept that there are two or more individuals involved, and it then follows, how many individuals, and which victims to attribute to which individual. A quick glance at the map below would seem to place Nichols as an outlier, and her inclusion in any group would have a marked effect on the shape of the resultant map compared to map that excludes her. Likewise, the inclusion/exclusion of any victim would have a marked effect on any result, as would increasing/decreasing the number on perpetrators.

I suppose that I am just wondering as to how useful a map prepared using modern scientific analysis can be when the input data is so uncertain?

Best regards, George

Hi George,

I wouldn't call the C5 arbitrary, all but Stride show all but unique characteristics with regards to the extent of the mutilations. Stride, of course, is included because of the proximity to Eddowes in both time and space given Stride was not mutilated. Of the non-C5, only McKenzie shows injuries that seem to indicate an aborted attempt at abdominal mutilations. Why those mutilations were less extreme than those of the C4 (C5 - Stride) is unknown, and either she's part of the series and for some reason JtR didn't go as far as he had in the past, or she's the victim of some sort of copy-cat who just couldn't bring himself to do anything further.

Anyway, linkage, or the determination of what crimes go together, is the first step. Mapping is what you do once you've determined what the series is, or at least what you believe it to be. Having tested some of the spatial analysis routines, I can tell you they are pretty robust (for the most part) against some noise, meaning if you leave out one of the offenses, or include one you shouldn't, etc, then often the analysis you get is very similar to when you include only the correct locations.

However, some locations do carry more information/weight than others. For example, including Tabram really doesn't change much at all but if we remove Stride then there is a much more noticeable change. I don't think I've looked at what happens if we don't include Nichols, but that's because I can't really see a good argument for excluding her. But, just to see what happens, I've done so now and while that reduces the over all area, the primary area of interest doesn't really change all that much as again, the routines are extracting a sort of underlying pattern. It's like if you weighed a dozen eggs and calculated the average weight for an egg. Sure, if you broke one before you had the chance to weigh it the average will be a bit different than if you weigh all 12, or if you had one left over from your previous dozen so included it and weigh all 13, again, the average will not be identical, but you'll still get a very similar estimate. It will be robust against such changes because the average weight of an egg is the underlying pattern and individual eggs are just varying around that patterned value.

Anyway, you are correct though, if you stuff up the linkage badly enough, particularly if the series you enter for analysis is a mixture of multiple different offenders, then the analysis will give you a result, but it will be pretty meaningless. Sort of like weighing some eggs, but sometimes you put in bacon, and sometimes you put in some butter, the odd onion, etc. Yes, you can get an average weight, but it doesn't represent the average weight of an egg any more. There's nothing about the analysis that can tell you "oh no, that offense wasn't Ted that was Charlie", it just spits out an analysis based upon what you put in - it presumes you've done your linkage properly so it doesn't do your chores for you. And as they say, garbage in garbage out.

- Jeff

**Hakeswill** · 04-18-2022, 05:42 PM

Hi Jeff,

Thanks for taking the time and effort to post about Bayesian statistics!

I'm familiar with some of the more 'standard' types of statistics, but I'm trying to get my head around the Bayesian approach a little more. Anyone who is interested to how this approach might work may want to have a look at this; using a Bayesian analysis of the Hae Min Lee killing that was popularised on the Serial Podcast. I won't spoil their suggestions in case you want to look at it, but they approach the idea using a network of evidence to make comparisons depending on how likely each piece of evidence is likely to be true. Obviously it doesn't prove anything, but I do think the approach can be useful in forcing you to evaluate why you think a piece of 'evidence' is more likely to be useful. I'm aware I use 'evidence' in quote marks a lot, but I can't think of a more useful term, even though there is very little evidence in this case.

One of the things that has struck me with many JtR suspects is that people are forced into making comparisons with other cases, solved or not, and I don't always feel it is justified. That's why having some more solid data like from solved cases based on geo profiling could be useful. I would be interested to see if cases that are known to have a limited area for the perpetrator to cover, essentially before widespread car use, follow the same patterns, though I realise such data may be rarer and harder to come across. I think there is also something linked to perceived boundaries that plays into how offenders view their range. I'm thinking here of the Middlesex Road boundary with the City.

Notblamedfornothing - I included the idea of JtR being comfortable talking to the people as there is at a decent possibility, I believe, that he was seen talking to some of the victims at least once, possibly more times, and that in at least three of the possible sightings the women were comfortable enough to go with him despite the potential danger. Granted, in the case of AC there was possibly less concern than if it was later in the series of events. If he was more of an ambush style attacker, this would not be as much of an issue, but that would reduce the importance of any of the witness sightings of someone talking to a victim.

Incidentally, given your name, I've always been confused as to why with the graffito, the version from Detective Halse, "...not the men..." was rejected by the Met and the Home office over PC Long's version. I would have assumed that a detective would have been better at recording details than a PC, but there must have been some reason. I wonder if there was something of an 'our area, our version' employed by the Met here.

Happy Easter to everyone,

H

1 Prior knowledge of the area of the crimes 90 %	JTR able to move easily through area and avoid detection soon after crimes
2 Suspect by named police on the ground 50 %	Lowered because of varied responses by different police involved and method of revealing names
3 Anatomical knowledge 75 %	Not necessarily medical, but I don't think someone without some knowledge could have reasonably easily located and removed organs in the the situation without having an idea oh at least mammalian anatomy. I'm aware that doctors differed on their view of this.
4 Exhibiting obvious signs of mental illness 40 %	I feel this hangs a lot on current knowledge of mental health at the time that may have coloured expectations. There are examples of serial murderers living otherwise 'normal' lives but that may depend a lot on expectations of those around them
5 Prior criminal acts 95 %	Problem is that they may not have been noted, so I don't think this is necessarily one of the big ones.
6 Suspect turns up in police reports somewhere 90 %	Though this evidence may well have been lost, I think chances are JTR was either questioned or mentioned somewhere, just from sheer number amount of police work
7 Able to put victims at ease 60 %	Revised this down. In more recent homicide cases involving sex workers, the need they had for money meant they had to out themselves in to more dangerous situations. Assuming he wasn't raving and screaming, I don't think he would have to have been particularly convincing in his chatter
8 Lived locally 80 %	could also have worked locally and moved into the area, but I think the geo data does point to someone based within the mile square.
9 Knew victims 10 %	Not as common in this type of crime, but location of crimes is quite a small area and I would imagine a fair chance that JTR would have known the areas, so may have been at least familiar with some faces
10 Caught 40 %	Obviously not meaning here that anyone was charged, but in similar cases something killers often require something external to stop them. That could of course be death by various means, but I find it less likely.

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Thought experiment (with numbers!). Suggestions welcome.

Thought experiment (with numbers!). Suggestions welcome.

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