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England and Wales Court of Appeal (Criminal Division) Decisions |
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You are here: BAILII >> Databases >> England and Wales Court of Appeal (Criminal Division) Decisions >> Thomas, R. v [2011] EWCA Crim 1295 (25 May 2011) URL: http://www.bailii.org/ew/cases/EWCA/Crim/2011/1295.html Cite as: [2011] EWCA Crim 1295 |
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ON APPEAL FROM THE CROWN COURT AT LUTON
His Honour Judge Bright QC
Ind nos. T20097336 & T20090352
Strand, London, WC2A 2LL |
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B e f o r e :
MR JUSTICE RODERICK EVANS
and
HIS HONOUR JUDGE NICHOLAS COOKE QC
(sitting as a Judge of the Court of Appeal Criminal Division)
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The Queen |
Respondent |
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- and - |
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Ashley Kieron Thomas |
Appellant |
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Jane Bickerstaff (instructed by the CPS) for the Respondent
Hearing date : 7 April 2011
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Crown Copyright ©
Lord Justice Richards :
The expert DNA evidence
"Both Dr Syndercombe-Court and Miss Cornelius were in agreement that the level of DNA present bordered the threshold described in the R v Reed and Reed ruling and was such that stochastic effects needed to be considered.
It was agreed that the level of DNA amplification was good, but that it deteriorated at the high molecular weight loci, as expected. None of the alleles observed were below threshold.
It was agreed that stutters and artefacts had been considered and taken into account.
It was agreed that the results had a good level of reproduction generally, with only low levels of possible drop in.
It was agreed that there were variable levels of stochastic variation throughout the result, which could be due to the relatively low amount of DNA and the enhanced process used. It was agreed that the stochastic variation at all loci except D2, D18 and FGA was minimal or acceptable. It was agreed that the stochastic effects at the high molecular weight loci, in particular D2 and FGA, were the main reason for not being able to assume the prominent alleles were from one contributor and therefore, there was no major profile.
It was agreed that all of the components of Ashley Thomas' DNA profile were represented within the LCN results obtained.
It was agreed that the results were unsuitable for any kind of statistical evaluation.
….
Summary
Dr Syndercombe-Court and Miss Cornelius agreed on the quality of the result and that it was suitable for some interpretation, but not for statistical evaluation as the stochastic effects at the high molecular weight loci introduced some doubt as to whether the prominent alleles were from more than one person. However, the phrasing and significance of finding all of the components of Ashley Thomas' DNA profile represented within the LCN results was not agreed upon …."
"To reiterate: all of the components of Ashley Thomas' profile appear in the DNA mixture.
I have considered the following two propositions:
- Ashley Thomas was a contributor and some of the DNA recovered was from him; or
- Ashley Thomas was not a contributor and none of the DNA recovered was from him.
If the first alternative were true, I would expect all of the components in Ashley Thomas' profile to be present in the mixed DNA result.
If the second alternative were true, I would have a low expectation of finding components which matched all of the components of Ashley Thomas' profile in the DNA mixture, as simulation experiments have indicated that it is rare to observe all 20 components by chance alone.
Therefore, in my opinion, the DNA profiling evidence provides support for the view that some of the DNA recovered was from Ashley Thomas, but I am unable to quantify the level of this support.
Furthermore, I agree that there are many other combinations of DNA components in different profiles that could produce the mixed results obtained."
"She said that her experience, however, as a forensic scientist for 12 years, dealing in DNA supported the findings of the simulation experiments and agreed with the conclusion drawn from them that it was rare to find all 20 components of a DNA profile by chance."
"However, she agreed that the bottom line was that she could give no statistical evaluation of what the word rare meant and she accepted that her findings really did not enable her to say that the defendant had handled the Baikal pistol."
"She said that in scientific terms, the most you could say from the DNA results was that you could not exclude – this is the form of words she is keen to sign up to – she said that the results could not exclude the defendant from being a contributor to the DNA mixture, but she fundamentally disagreed with the opinion expressed by Miss Cornelius that the results provided support for the view that some of the DNA may have come from the defendant. She said that was going too far.
She said that Miss Cornelius' opinion in her view was based on the assumption that the 20 components which matched the defendant's profile have come from one individual, whereas it is not possible, she said, as a scientist to say that they have all come from one person."
"Dr Syndercombe-Court felt that Miss Cornelius' interpretation (when she said that 'it is rare to observe all 20 components by cahnce') was of a type known as 'Random Man Not Excluded' or probability of inclusion/exclusion, which is accepted for use in other European countries but is not generally accepted in this country for use in court due to its limitations and inherent prosecution bias. Miss Cornelius disagreed with this view and felt that her evaluation used the likelihood ratio framework, but she also conceded that she did not have an in-depth knowledge of RMNE calculations and had not dealt with RMNE in a casework setting as it was not used by the Forensic Science Service.
Miss Cornelius felt that making the comment that Ashley Thomas could not be excluded as a contributor, but without qualifying this comment further could lead to misunderstanding. Dr Syndercombe-Court disagreed and stated that to go further required an assumption that the prominent alleles must be from one individual. Miss Cornelius disagreed with the requirement of making that assumption.
Dr Syndercombe-Court preferred the suggested alternative wording that was in Miss Cornelius' casefile record of the discussion with Drs Evett and Pope, but Miss Cornelius stated that the alternative wording did not change the conclusion that had been agreed during the discussion.
Summary
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Dr Syndercombe-Court is of the opinion that 'providing support' is overstating the evidence. Miss Cornelius is of the opinion that making no further comment than 'cannot exclude' is failing to provide additional scientific information that could be of use to the court."
The application to exclude the DNA evidence
"The courts of England and Wales have become familiar with the kind of statistics commonly associated with DNA profiling, but whereas here, a statistical evaluation is not possible, I see no reason why experts should not be permitted to express an opinion on whether the results provide support for the view that some of the DNA recovered was from the defendant, as the Crown's expert contends, or whether they merely establish that the defendant cannot be excluded as a contributor to the DNA mixture as the defence expert argues."
"There is no doubt that the DNA experts for the prosecution and the defence take a different view as to how the DNA results should be interpreted. The criticisms made by the defence of the opinion expressed by Miss Cornelius can be fully aired before the jury and in my judgment, there is nothing unfair about the jury being allowed to hear and decide for themselves about the different opinions expressed by the two DNA experts.
In the circumstances, this is not a case for the exercise of my discretion under s.78 of the Police and Criminal Evidence Act 1984 to exclude the evidence of Miss Cornelius."
The appeal against the ruling
"23. On principle, we accept the caution with which any expression of conclusion in relation to evidence of this kind (and others) needs to be approached. We agree that the fact that a conclusion is not based upon a statistical database recording the incidence of the features compared as they appear in the population at large needs to be made crystal clear to the jury. But we do not agree that the absence of such a database means that no opinion can be expressed by the witness beyond rehearing his examination of the photographs. An expert who spends years studying this kind of comparison can properly form a judgment as to the significance of what he has found in any particular case. It is a judgment based on his experience. A jury is entitled to be informed of his assessment. The alternative, of simply leaving the jury to make up its own mind about the similarities and dissimilarities, with no assistance at all about their significance, would be to give the jury raw material with no means of evaluating it …
31. We conclude that where a photographic comparison expert gives evidence, properly based upon study and experience, of similarities and/or dissimilarities between a questioned photograph and a known person (including a defendant) the expert is not disabled either by authority or principle from expressing his conclusion as to the significance of his findings, and that he may do so by use of conventional expressions, arranged in a hierarchy, such as those used by the witness in this case …. They are, however, expressions of subjective opinion, and this must be made crystal clear to the jury charged with evaluating them."
The judge's directions to the jury on the DNA evidence
The submission of no case to answer
"Mr Griffiths explained that he had looked at x-rays showing the bullet still lodged in Mr Akinboro's body. He also examined Mr Akinboro's clothing and he concluded that the bullet was slightly distorted and you will remember how he took you through the photographs of Mr Akinboro's clothing …. They show that the bullet hole was at the top of the zipper of Mr Akinboro's jeans and that there are two or three teeth missing, and he concluded that what he saw would account for the damage to the bullet shown on the x-ray.
He told you that he carried out tests on the bullet hole in the jeans and the pants beneath to see if there were any traces of copper or nickel which you know are both used to make jackets for bullets, and he found on the edge of the bullet hole that there was a deposit of lead, but could find no evidence of copper or nickel. He concluded that this could either be because the bullet was an unjacketed lead one, or that it was a jacketed bullet fired through a dirty barrel which would mask any copper or nickel that might be present."
In cross-examination, as the judge also reminded the jury, Mr Griffiths accepted that the fact that the tests had been positive for lead and negative for copper and nickel "made it most likely that the bullet which entered Mr Akinboro's body was an unjacketed one".
"As I got out of the police car, I heard a gun shot. The area is heavily built up with lots of tall concrete buildings which cause sound to reverberate. It was not possible to say where the sound came from."
Conclusion