A6 Murder DNA evidence

[Victor]

Hi Reg,

The judges may have ruled out the possibility of contamination but the respondents certainly did not.

The judges said they could not exclude the possibility of contamination, but the results rule out contamination having occurred.

Do I assume correctly that your summary of what they say is confined to the judges alone?

Nope, it's everyone except Dr Evison who remains unconvinced despite not being able to give a valid explanation the results obtained.

KR,
Vic.

Hi Vic

Hi Reg,

Reading the transcript again, I realised that judgment does rule out contamination, but they do not rule out the possibility that contamination could have happened. Potentially it could have occured, but it didn't.

A summary of what they say in totality is the possibility of contamination could not be ruled out, but the results show that no contamination occurred

KR,
Vic.

The judges may have ruled out the possibility of contamination but the respondents certainly did not.

Do I assume correctly that your summary of what they say is confined to the judges alone?

Regards
Reg

[Victor]

You will have to explain the difference between the "possibility of contamination could not be ruled out" and "contamination could not be ruled out".

Hi Reg,

Reading the transcript again, I realised that judgment does rule out contamination, but they do not rule out the possibility that contamination could have happened. Potentially it could have occured, but it didn't.

A summary of what they say in totality is the possibility of contamination could not be ruled out, but the results show that no contamination occurred

KR,
Vic.

[Victor]

Hi Reg,

I had a further thought over lunch. Try defining the following terms as a percentage (or range of percentages):-

Impossible
Possible
Improbable
Probable

You'll find that they aren't exact opposites of eachother.

KR,
Vic.

[Victor]

All but 2 other countries wouldn't touch LCN with a barge pole for lead evidence in criminal investigations.

Hi Reg,

Have you got a reference for the above quote?

LCN is a developing forensic tool, and as far as I am aware every investigative organisation is interested in how it is developing, with the hope of eventually getting a tool as robust as SGM+. Obviously that can't happen unless it is used and evaluated.

Have you got any information on how long it took for SGM+ to gain the approval it has now?
How does that timescale compare for LCN?
What about fingerprinting and other forensic tools?

Do you think LCN will ever provide useful results? Or should it just be abandoned now?

KR,
Vic.

[Victor]

You will have to explain the difference between the "possibility of contamination could not be ruled out" and "contamination could not be ruled out".

Hi Reg,
That's what I attempted to do in the last post.
contamination is a statistical probability event - one of your links states that in the worst case examined the probability is 70%
"contamination could not be ruled out" - could imply that "contamination definitely occurred"
"the possibility of contamination could not be ruled out" - means that the probability applies - some will be contaminated, some won't.

I will go one further and say that the use of the word possibility indicates that the respondents do not know for sure if contamination existed or not in their tests!

That's perverting an obvious probability prediction. Every experiment is susceptible to contamination, and scientists do everything to eliminate or quantify it - hence the "Good Practice" guidelines, advice on how to minimise the possibility of contamination, but sometimes you can't guarantee to eliminate it.

In other words - Scientists do not know for sure if their experiments will be contaminated, only by examining the results can they say whether it occurred or not (or sometimes "may have occurred").

The use of the word possibility (prior to discussing the results) indicates that contamination is probabilistic - it cannot be guaranteed to occur nor to not occur. The words "But that is to ignore the results of the DNA profiling" indicates that they were discussing their expectations - they expected to possibly find extra contamination profiles, but in actuality found none.

KR,
Vic.

So once again, what was your attitude to the proposed DNA testing before it happened, and what were your expectations? Can you say hand on heart that you would have beaten the same DNA drums had Alphon put his stamp in the right places and Hanratty not shown up at all? Would you have embraced an easy but futile argument that the potential for contamination can never really be ruled out?

Hi Caz
My attitude was one of DNA should be correct and my expectation was that the DNA tests would show that no DNA from Hanratty would be found because I believed and still do that Hanratty had nothing to do with the A6 murder whatsoever.
As far as Alphon is concerned, he was at that time and still is alive. The DNA would have been put to him and he may or may not have confessed. It would then be up to the CPS to see if a convincing case could be brought before a jury.
For your further interest I was totally and utterly unaware of the existence of LCN DNA until what has happened in the last year. With the Templeton Woods case and especially Hoey (Omagh Bombing appeal), LCN has been shown to be riddled with crippling problems that make it pretty worthless as anything other than an itelligence tool. All but 2 other countries wouldn't touch LCN with a barge pole for lead evidence in criminal investigations.
Have you read any of the articles about LCN linked to on here? If not I would suggest having a look. Most are nicely layman targeted so should not pose any problems in understanding

Regards
Reg

[caz]

Hi Caz,

Surely there must be (at least one) sample taken from the non-mucous areas, because of the "only places". And those sample(s) must have shown no DNA at all.

KR,
Vic.

Hi Vic,

Well that’s what I’m sure is implied, but the language is slightly ambiguous:

The only DNA extracted from the handkerchief came from James Hanratty. The only places on the handkerchief from which his DNA was extracted were the areas of mucus staining.

Someone who sees manipulation and skulduggery everywhere could infer from this that the only places they took samples from were ‘the areas’ of mucus staining, in which case they would only have tried to extract DNA from those areas, and might have missed some extractable DNA in the non-mucous areas. I don’t for a moment believe this is what is meant here, but it could have been worded a bit more tightly for the layman, to allow no wriggle room, eg:

The only DNA extracted came from James Hanratty, and only from the areas of mucus staining. No DNA was detected anywhere else on the handkerchief.

That would more clearly imply attempts to detect/extract DNA from all areas that bore no fruit.

Hi Reg,

With respect, it’s a bit of a cop-out in general (and a misrepresentation in this case) to claim that contamination could not be ruled out. As Vic has explained it’s the potential for contamination that can rarely if ever be ruled out entirely, no matter what case you fancied getting your teeth into - not the actuality, which was as good as ruled out in Hanratty’s case by the very clear findings in combination with all the known circumstances.

The contamination issue becomes meaningless if nobody could safely be convicted (or cleared of all suspicion for that matter) with the help of DNA testing as long as there had been a potential for contamination, regardless of whether any could be found, indicated or even reasonably suspected. It has to come down to what is seen as overwhelmingly likely or unlikely to have led to the results in each case.

If the Hanratty results had been any vaguer than they were, or ambiguous or inconclusive, or had produced an uneasy mix of unidentifiable or unsourced DNA profiles along with any identifiable ones from expected sources, then fine - the spectre of contamination virtually introduces itself and shakes hands with all interested parties.

But at some point you have to demonstrate how a theoretical contamination event could have become the reality and contributed to the very specific findings in this case, when others saw it as implausible to the point of conceding a long, sincerely fought, but ultimately uneven struggle. Hanratty - and only Hanratty - was found crawling all over the hanky and knickers, for all the world like he stamped his ownership on them on that dreadful night back in 1961. And not a trace of the man whose claims to that ownership you so wanted to believe.

The only DNA evidence I would accept is that carried out using SGM+, or an equivalent, following the correct guidelines for that system. For these systems produce reliable replicate samples.

So once again, what was your attitude to the proposed DNA testing before it happened, and what were your expectations? Can you say hand on heart that you would have beaten the same DNA drums had Alphon put his stamp in the right places and Hanratty not shown up at all? Would you have embraced an easy but futile argument that the potential for contamination can never really be ruled out?

Love,

Caz
X

Hi Vic

The above is wrong. The possibility of contamination could not be ruled out.

You will have to explain the difference between the "possibility of contamination could not be ruled out" and "contamination could not be ruled out".

I will go one further and say that the use of the word possibility indicates that the respondents do not know for sure if contamination existed or not in their tests!

Regards
Reg

[Victor]

Contamination could not be ruled out by the respondents.

Hi Reg,

The above is wrong. The possibility of contamination could not be ruled out.

There are 3 possible alternatives (the 4th being impossibile)

1. Contamination: Possible but didn't occur.
2. Contamination: Possible and did occur.
3. Contamination: Impossible and didn't occur.

The 4th being contamination is impossible but did occur - which is the situation that couldn't happen.

You seem to repeatedly confuse the first two situations. All the experts rule out situation 3 above, whereas you are saying that they ruled out both situation 3 and situation 1, which is just not true.

Either that or you are denying that situation 1 above could occur. The experts are all saying that what happened was situation 1 - contamination could have occured but random chance means it didn't occur.

KR,
Vic.

[Victor]

Yes, 'places' and 'the areas' would imply at least two DNA extractions from the hanky, both of which were found to match DNA taken from Hanratty's dead body.

Hi Caz,

Surely there must be (at least one) sample taken from the non-mucous areas, because of the "only places". And those sample(s) must have shown no DNA at all.

KR,
Vic.

Hi caz

Interesting ?'s but not mutually exclusive as I will show.

Using SGM+ or other such validated technique, a suspect can be excluded. Using LCN no such exculporary means are possible. The original amount of template used for LCN testing is below the stochastic thresholds of SGM+. Therefore allelic drop in and out is never reproducable from one replicate to another. Interpretation becomes arbitrary even if two analysts are working on the same sample.

Do you think Hanratty's DNA was on the knicker fragment, was correctly identified, but got there innocently?

I don't know.

Contamination could not be ruled out by the respondents.

Do you think the rapist's DNA was ever there? If so, was it misidentified, undetectable or just missed?

Again, I don't know.

Certainly LCN would have been of little help here as a mixed profile would have been produced. See articles on LCN for the problems associated with it.

Or do you think the fragment was rapist-free and Hanratty-free and the DNA recovered from it simply not attributed correctly, either to the right individuals or the right number of individuals?

Sorry to sound boring but again I don't know.

See stuff on mixed profiles that have been posted here.

I'm still trying to ascertain what, if anything, you were expecting the DNA analysis to show, and what findings, if any, you would have accepted.

The only DNA evidence I would accept is that carried out using SGM+, or an equivalent, following the correct guidelines for that system. For these systems produce reliable replicate samples.

Reg

[caz]

Hi Vic,

Yes, 'places' and 'the areas' would imply at least two DNA extractions from the hanky, both of which were found to match DNA taken from Hanratty's dead body.

But it would have been misleading to imply that there was no non-Hanratty DNA to be extracted from anywhere on the hanky, or the Hanratty DNA was confined to 'the' areas of mucus staining, if they hadn't tested the non-mucus-stained areas and all the mucus-stained ones. Obviously more than one person could in theory have blown their nose on that hanky, and any number, in theory, could have handled it and left traces at some point, even if only Hanratty's mucus actually survived to tell the tale.

It would also be extremely misleading to describe any finding as a 'typical' distribution if it was based on guesswork and assumption, and not what had 'typically' been observed whenever it was known that sex had indeed taken place between the two parties whose DNA showed up.

Love,

Caz
X

[Victor]

I readily admit that I’m no scientist, but I can interpret the written word well enough to know when someone else is misinterpreting it. This could be because their language skills are not up to their scientific ones, but if it’s a case of trying to blind me with the science it won’t work.

Hi Caz,

From para 126 of the judgment:-

The only DNA extracted from the handkerchief came from James Hanratty. The only places on the handkerchief from which his DNA was extracted were the areas of mucus staining.

From the above quote how many times do you think the hanky was sampled and DNA tested?

My bet is "at least 2", but I wonder if we can conclude it's any more than that.

KR,
Vic.

edit: I supposed the same reasoning would have to apply to:-

With regard to the knicker fragment we have what Dr Whitaker would describe as a typical distribution of male and female DNA following an act of sexual intercourse leading, to the obvious inference that the male contribution came from James Hanratty.

[caz]

Hi again all,

Reg, could I ask you what you think got screwed up here?

Do you think Hanratty's DNA was on the knicker fragment, was correctly identified, but got there innocently?

Do you think the rapist's DNA was ever there? If so, was it misidentified, undetectable or just missed?

Or do you think the fragment was rapist-free and Hanratty-free and the DNA recovered from it simply not attributed correctly, either to the right individuals or the right number of individuals?

I'm still trying to ascertain what, if anything, you were expecting the DNA analysis to show, and what findings, if any, you would have accepted.

Love,

Caz
X