A6 Murder DNA evidence

[Victor]

Dr Evison when cross examined was possibly asked whether he wholeheartedly disputed the fact that the contamination must have been via semen as was put by the respondents. He could have said that if that is what the forensic results had found he would possibly concur but then went on to say that he believes any other form of contamination was a distinct possibilty given the life cycle of the evidence and the sensitivity of the test involved.
Remember he was outgunned by about to 5 to 1 with regard to expert scientific witnesses.
Reg

Hi Reg,

Unfortunately that explanation isn't compatable with the quote "Dr Evison seems to accept that in the case of the knicker fragment the contaminant would have to be semen" from para 120 of the judgment. It explicitly says that any other form of contamination has been ruled out.

KR,
Vic

[Victor]

Hi all

The car, when found had no forensic evidence that pointed to a third party bar VS and MG.

I agree, but we are talking about 1961 forensic ability.

Lets accept that VS and MG had sex in the car prior to being waylaid.

Why specifically "in the car"? Why not over the bonnet?

When VS was raped where did the rapists semen go? It seems highly unlikely that some would not have remained in the car. None was found on any of VS clothing bar her knickers and a slip.

Why "highly unlikely"? If the rapist ejaculated inside VS, and she replaced her underwear quite soon then it is possible that her underwear retained the ejaculate.

A nurse on seeing VS when she was admitted to Bedford General stated that her knickers were not on correctly.

I have seen this mentioned before, but I have not seen the source for this assertion.

If she did not pull her knickers up completely then even if the rapist did ejaculate inside of her then his semen would not have made such an impression on her kincker crotch area (and 5 inches up the back).

I don't see where you are going with this. The physical evidence is that there was some type-O semen on the underwear and MG is type AB so it could not have been his.

A piece of the crotch area was stored away and later found in 1991.

The rest of VS's knickers were destroyed in 1962.

Reg

Yes, I agree, the knickers were examined and a piece was removed in 1961 before the trial and stored away and later found in 1991. The rest of the knickers were presented at the trial and destroyed shortly afterwards in 1962.

KR,
Vic.

[caz]

Hi Caz
Re my post #58
I would like to apologise unconditionally for what I said, which was extremely harsh to say the least and I have no excuses. I hope that you accept my apology and that we can move on.

Re your post above
I am not sure what you mean by conclusion in the second paragraph. Besides, why was the LCN DNA technique needed. Traditional methods such as SGM+ had not detected conclusive profiles? The original evidential bodily fluids and tissue had degraded to a degree where only microsopic pieces of useful DNA where left, hence the use of LCN.

Kind regards
Reg

Hi Reg,

That is most gracious of you. I always accept apologies and I knew you were an old softie really.

All I meant was that the evidence obtained from the remaining ‘useful DNA’ you refer to led the experts to conclude that Hanratty was indeed the rapist. Even if the evidence could be shown to be flawed or unreliable, Hanratty could still have been the rapist whose DNA had degraded beyond recovery or gone AWOL with the rest of the knickers. The conclusion would in that case have been right, but for all the wrong reasons. Obviously, if the conclusion was wrong, it must have been someone else’s DNA that was no longer detectable, and Hanratty’s must have got there by some other route.

Hi James,

I don’t pretend to understand anything about how different cell types degrade, or the rate at which they do it, or the maximum shelf life of sperm or semen before their last remaining identifying features take their leave, or how long after that any useful DNA left behind can survive before that too bites the dust. As a complete airhead when it comes to science, I find it fascinating that deep frozen sperm can produce a healthy living human being fifteen years later (or was it twenty-five?) and yet they whack a ‘consume within six months’ label on a frozen meal.

Wherever Hanratty’s DNA came from, it was identified on the knicker fragment as well as the hankie, and nobody to my knowledge has suggested that it arrived in either place any later than 1961/2. We also have VS’s DNA from 1961, presumed to have originated from vaginal fluid, and AB group DNA, presumed to have come from the AB group semen found in 1961, which was then assumed to be MG’s.

If we do our own presuming and disregard the DNA that may not have been confirmed as MG’s, we still have three sets - two from JH and one from VS - that must have survived from 1961/2 without degrading beyond detection. Would that not have narrowed down the possibilities concerning whether the DNA originated from seminal, vaginal or nasal fluid, saliva, sweat, hair or skin cells?

What do you think JH’s DNA on the knicker fragment could have come from, apart from his semen? Are the possibilities endless, or do they each have their own expiry date?

Love,

Caz
X

[reg1965]

That is most gracious of you. I always accept apologies and I knew you were an old softie really.

Cheers.

All I meant was that the evidence obtained from the remaining ‘useful DNA’ you refer to led the experts to conclude that Hanratty was indeed the rapist. Even if the evidence could be shown to be flawed or unreliable, Hanratty could still have been the rapist whose DNA had degraded beyond recovery or gone AWOL with the rest of the knickers. The conclusion would in that case have been right, but for all the wrong reasons. Obviously, if the conclusion was wrong, it must have been someone else’s DNA that was no longer detectable, and Hanratty’s must have got there by some other route.

Correct.

Reg

[Victor]

Whitaker

On the A6 thread the World's End case has been mentioned, and there's a link here -> http://www.guardian.co.uk/science/2007/sep/16/dna

Taking some quotes from that article.

"Whitaker is one of the world's most highly respected DNA profilers and has helped to convict a string of killers"
"Whitaker has a careful, precise manner - perhaps a result of his need for exactitude in his work"
"Whitaker is the epitome of caution"

Just thought I'd include those to counteract other comments on this thread.

KR,
Vic.

[Dupplin Muir]

Hello Victor

Hmm...I'm not sure I'd put too much weight on press encomia of forensic scientists: I can remember all too well the praise lavished on Professor James Cameron, before it came out that his testimony had helped to convict innocent people in both the Maxwell Confait and Lindy Chamberlain cases (as well as who knows how many others).

You might add the forensic scientists who testified against the Birmingham Six and Sally Clark.

The problem I have with Dr Whitaker is why, if the LCN DNA method is so reliable, does he pop up in criminal cases as far away as New Zealand? Surely there must be some other laboratory that would be closer?

It seems to me, after Googling about a bit, that elsewhere in the world LCN is seen as basically exculpatory: only FSS seem to think that it is capable of proving a suspect's guilt.

Here are another couple of interesting sites and I've extracted some points that seem relevant to the A6 case.

http://www.scientific.org/tutorials/articles/riley/riley.html

PCR-based testing often requires less DNA than RFLP testing and the DNA may be partially degraded, more so than is the case with RFLP. However, PCR still has sample size and degradation limitations that sometimes may be under-appreciated. PCR-based tests are also extremely sensitive to contaminating DNA at the crime scene and within the test laboratory. During PCR, contaminants may be amplified up to a billion times their original concentration. Contamination can influence PCR results, particularly in the absence of proper handling techniques and proper controls for contamination.

...

Prevention of false results involves the use of carefully applied controls and techniques. As described later, such controls and techniques can rarely guarantee that contamination hasn't influenced the results. In forensic DNA testing, some of the scientifically worst-case scenarios can be prevented by keeping DNA samples from known individuals well out of range of other items of evidence at all stages. Most forensic DNA laboratories perform negative controls, blank samples that will often detect contaminants in the laboratory. The blanks detect contaminants by showing partial or full DNA profiles representing the contaminants. Alternatively, the blank may show no profile, consistent with, but not proving that contamination didn't occur. Unfortunately, a few forensic DNA laboratories omit their controls. A few favor the controls by using special equipment on them, or by not carrying them through the entire procedure. Such practices are hazardous, especially when an important evidentiary sample has a low amount of DNA, degraded DNA, or otherwise presents as a minimal or partial (see below) sample. In short, while PCR is a useful research tool, all applications require extreme care and vigilance.

...

It is critically important to store samples in proper containers and keep known samples well-segregated from other evidence, particularly evidentiary samples that have small amounts of DNA. Paper envelopes or wax-paper folds are unsuitable containers.

...

The laboratory should be extremely careful not to overstate the scientific value of the evidence. For example, reports that a profile occurs in 1 in a billion, randomly selected individuals greatly overstate the proven error rate of the technology since false convictions based on DNA evidence have been established. Perhaps such rare match probabilities could be reached if thoroughly independent samples produced the same results in multiple, independent, non-communicating laboratories. But, for single laboratories, extremely rare match probabilities misrepresent the scientific value of technology.

http://www.aclu.org/privacy/biotech/asset_upload_file971_29096.pdf

The potential for error in DNA testing is exacerbated by the context in which labs carry out their work. Lab technicians do not typically “blind” themselves to the government’s expected or desired outcome. Studies have revealed lab notes that indicate that analysts are familiar with facts in their cases and are aware of which results will help or hurt the prosecution. For example, one set of notes stated, “Death penalty case. Need to eliminate [other individual] as a possible suspect.” It is a well-established psychological phenomenon that people tend to see what they expect to see, particularly in ambiguous situations.

I don't think that anyone can say that these caveats don't apply to FSS, since it appears that they reject any independent oversight of their work.

Again, apologies for the length of this post!

All the best

FSS

[Dupplin Muir]

Hello all

I finally got around to watching the 2002 'Horizon' on the A6 murder, and I fear that it rather fell into its usual trap of 'trust the men in the white coats'. I was also rather surprised that it used the false logic of asking 'if JH wasn't the rapist, where's the rapist's DNA?'

I believe this was mentioned on the old thread, but one counter to this argument would be that the rapist was azoospermic. The website

http://www.andrologyjournal.org/cgi/content/full/23/3/293

puts the incidence of this condition at 2%. Given some of the improbabilities and coincidences surrounding this case, odds of 50:1 seem like a racing cert!

DM (not FSS: that was me playing around with the post in Notepad and not proofreading properly!)

[Victor]

Hello all

I finally got around to watching the 2002 'Horizon' on the A6 murder, and I fear that it rather fell into its usual trap of 'trust the men in the white coats'. I was also rather surprised that it used the false logic of asking 'if JH wasn't the rapist, where's the rapist's DNA?'

I believe this was mentioned on the old thread, but one counter to this argument would be that the rapist was azoospermic. The website

http://www.andrologyjournal.org/cgi/content/full/23/3/293

puts the incidence of this condition at 2%. Given some of the improbabilities and coincidences surrounding this case, odds of 50:1 seem like a racing cert!

DM (not FSS: that was me playing around with the post in Notepad and not proofreading properly!)

Hi DM,

I'll reply to your other post later, but to comment on the above point, it was established that MG is blood group AB, and they detected some blood group O sperm on VS underwear at the original trial, so that would mean that the rapist was not azoospermic and of blood group O.

KR,
Vic.

[Victor]

Here are another couple of interesting sites and I've extracted some points that seem relevant to the A6 case.

http://www.scientific.org/tutorials/...ley/riley.html

Hi DM,

I've just read through this link and it does contain some very relevant points - in particular the part where it describes centrifuging the sample to seperate the sperm and non-sperm DNA so that a DNA profile of just the sperm is possible.

Now that really is very interesting if it was used in the A6 case!

KR,
Vic.

[reg1965]

Hi DM,

I've just read through this link and it does contain some very relevant points - in particular the part where it describes centrifuging the sample to seperate the sperm and non-sperm DNA so that a DNA profile of just the sperm is possible.

Now that really is very interesting if it was used in the A6 case!

KR,
Vic.

Hi Vic

Whether it was used or not it still does explain how no other profiles were found on the hanky, considering how many persons may have handled it!

Reg

[Victor]

Hi Vic

Whether it was used or not it still does explain how no other profiles were found on the hanky, considering how many persons may have handled it!

Reg

Hi Reg,

Yes but it does very nicely explain why any contamination on the knicker fragment would have to be semen! Because the DNA profiles came from the semen-only fraction.

And of course your qualifier I've highlighted above explains the hanky perfectly well.

KR,
Vic.

[reg1965]

Hi DM,

I've just read through this link and it does contain some very relevant points - in particular the part where it describes centrifuging the sample to seperate the sperm and non-sperm DNA so that a DNA profile of just the sperm is possible.

Now that really is very interesting if it was used in the A6 case!

KR,
Vic.

Hi Vic
What did you make of the rest of the 2 articles that DM posted? Are you just cherry picking the bits that make you feel good? Ostrichs bury their heads in the sand too!

Reg

[Victor]

Hi Vic
What did you make of the rest of the 2 articles that DM posted? Are you just cherry picking the bits that make you feel good? Ostrichs bury their heads in the sand too!

Reg

Pot, Kettle, Colour-check!

No, I haven't got round to reading the other article yet.

I did think that discovering a technique that would explain the "contamination would have to be semen" comment that has been a point of contention for quite a while was significant, whereas lots of "extreme care needed to minimise contamination" type comments are futile if there were no contaminant profiles detected.

The number of qualifiers used is astounding...(last sentence of the first paragraph DM quoted post #111)
"Contamination can influence PCR results, particularly in the absence of proper handling techniques and proper controls for contamination."

KR,
Vic.

[Dupplin Muir]

Hello Victor

It's funny how we can read different things into the same piece of text.

The number of qualifiers used is astounding...(last sentence of the first paragraph DM quoted post #111)
"Contamination can influence PCR results, particularly in the absence of proper handling techniques and proper controls for contamination."

I took that 'particularly' to mean that you can get contamination EVEN WITH 'proper handling techniques and proper controls for contamination'!

I can only conclude that it's a glass-half-full/glass-half-empty kind of thing!

DM

[Victor]

Hi DM,

That's the thing about contamination, it's a probability game. You can have contamination even with proper techniques, and conversely you can have no contamination even with sloppy techniques.

Good techniques reduce the probability but doesn't eliminate contamination
Poor techniques increase the probability but doesn't guarantee contamination

Statistics and probability are confusing, even if you do understand Schrodinger's Cat.

KR,
Vic.