Its been a long while since I last posted to the blog. The closure of the Forensic Science Service has had the effect of paralysing debate on forensic science generally here in the UK to the point where it was difficult to make a contribution regarding anything else. Now that the FSS has closed and things are starting to settle down a little in the market, it is time to start discussing forensic science again. As Chief Scientist for Contact Traces, an ISO 17025 accredited laboratory, I have a keen professional interest in issues surrounding forensic quality. I am not an expert in any kind of area associated with forensic biology and make no comment as to the effectiveness of blood searching or the likelihood of false negatives. I have been an expert in several high profile cases (including Damilola Taylor and Stephen Lawrence) where the issue over missed blood has arisen, and have witnessed at first hand how they have been dealt with by both the prosecution and defence advocates, and the experts instructed by them.
In the case of Damilola Taylor, the failure to find blood by scientists from the FSS resulted in a government enquiry into the processes used to search for blood by forensic scientists. The enquiry held that:
Our conclusions (which are without hesitation or qualification), based upon documentary evidence and oral testimony, are that there was no systemic failure in the operations of the FSS; there were however human failures in implementing the operating procedures of the FSS which brought about the failure to recover crucial evidence; that evidence was Damilola’s blood on the right trainer (APR 60) said to belong to Danny Preddie and Damilola’s blood on a black “Giorgio” sweatshirt (APR 34) said to belong to Rickie Preddie.
and later that:
...no scientist however experienced or skilled can ever be guaranteed to find the evidence sought. Searching with the naked eye, with appropriate lighting, with microscopic aids and with the application of chemicals yields the right results in nearly all cases. But sometimes, due to human fallibility, there is failure. We do not believe that the failure rate is high; the FSS on the evidence will tolerate no acceptable failure rate and nor will any of the other Forensic Providers.
Whilst absolving the systems as error free, but the process not, the enquiry was content to recommend (albeit as an option) a second check:
The availability of a complete second scientific examination of an article should be considered as an option...
So the Damilola Taylor enquiry comes to an end recommending that if an item is found to be negative for blood that is should be searched completely a second time. Laboratories were not obliged to do this, but some did take it upon themselves to introduce such a second check, although it was left to their discretion as to who should do it, when it should be done, how it should be done and to what extent it should be done.
Whilst the Damilola Taylor case was concluding the government were busy implementing the key recommendation from the 1999 Mac Pherson enquiry into the case of Stephen Lawerence, that to change the law so as to allow suspects previously tried and acquitted, to potentially face a re-trial if new evidence met a legal threshold. This was made a statutory reality in Section 76 of the Criminal Justice Act 2003, which required that the CPS can seek a retrial for a suspect determined by a hearing at the court of appeal. The CPS would be successful if they could prove that the evidence was new, compelling and if a re-trial was in the public interest.
One of the first cases to test the new law was the murder of Vikki Thompson. Mark Weston was acquitted of the murder in 1996, however new examinations had revealed the presence of blood on a pair of his boots that yielded a DNA profile matching that of the victim. In echoes of the Damilola Taylor case, the court of appeal had to consider why the blood was missed the first time around, and crucially what the role of the forensic scientists was in this process and whether or not they were negligent in missing the blood.
The court held that:
...Although there have been very substantial advances in DNA science in the period from 1995 to the present, particularly in the improvement and validation of more advanced profiling, the basic techniques for detecting blood on surfaces such as boots have not materially changed. The search is still made using the naked eye and/or a microscope and the surface is rubbed with filter paper as part of the KM test or similar tests.
Further:
...we accept, that the examination of dark coloured boots for blood is in itself a difficult task. Furthermore, not only is the surface uneven, but it is difficult to examine them under a microscope. Because of these difficulties it is possible for a competent examiner not to find visible traces of blood.
The court of appeal has just come to the conclusion that there exists systemic error in the searching for blood, if perhaps only in a system for searching whereby a human being searches an item for blood (at least for items such as dark coloured boots), because they expect errors to arise when even a competent examiner performs the search.
Similarly in this case the issue over checking arose:
...The areas examined by Mr Mann in 1995 were not checked by Ms Miller in 1996 and the examination by Ms Miller in 1996 was not checked on its completion by Mr Mann. At that time it was not sufficiently appreciated that a second check was necessary.
The court appeared to believe that the recommendations of the Damilola Taylor enquiry have been implemented because the judges go on to state:
...two examinations are now required, though there must remain the risk that even two will not detect all the blood. Again it seems that another explanation as to why the blood might have been present but not detected was the failure to conduct two examinations of the same areas in 1995/6.
The court turned to consider the diligence of the forensic scientists in 1995/6 and they said:
...the powerful point was made on behalf of the respondent that whereas missing one area of blood might be explicable, missing at least four areas of blood was not consistent with a careful and diligent inspection.
Crucially the court took notice of the difference in the way the blood search was undertaken, and it appears that it is this point, and this point alone, which enabled the court to clear the FSS scientists of any allegation that they had acted without due diligence:
In clarifying this point the court stated that:Without the evidence of the change in practice and without the evidence of Ms Rosalyn Hammond and Ms Caroline Hughes, this would have been a very powerful submission. Ms Hammond and Ms Hughes agreed that blood stains can be missed on items such as boots, even when they have been examined by careful and diligent forensic scientists. However it seems to us in the light of that evidence, although we remained concerned about the circumstances of the original examination of the boots, it would be wrong for us to conclude that either Mr Mann or Ms Miller had acted without due diligence. It is clear that some criticism should attach to the FSS in not providing proper and up-to-date lighting in 1995/96, but again it does not seem to us that on its own we could say that that amounted to a failure of due diligence on the part of the FSS itself.
and crucially, in relation to possible future applications to re-prosecute with new evidence:At the time of the investigation in 1995/6, as we have set out at paragraph 37v) above, there was insufficient understanding of the fallibility of testing for blood and the necessity of a second and thorough check. Were it not for that lack of understanding, the question would have arisen (though we need not decide it) as to whether it is in the interests of justice, where an investigation is concluded and a matter brought to trial on the basis of scientific tests known to be fallible, that the powers under Part 10 of the 2003 Act can be used to re-open an investigation. We will merely observe that it is plainly in the interests of justice that there is an end to litigation.
Where a test is known to be fallible, every effort must be made to ensure accuracy; reliance should not be placed on the possibility of trying again under Part 10.a
The court has stated clearly here that the traditional process for searching for blood is now known to be fallible, because the scientists have stated so. This, according to Tim Roberts QC, could have serious implications:
The reason for the abolition of the double jeopardy principle was to preserve respect for the Justice system after the anticipated advance of science had made a mockery of past verdicts based upon inferior forensic scientific techniques.
However, once it is known that a particular test is ineffective, it will not do in future to use it, fail to secure a conviction, and later hope to make a section 76 application when you have more time and resources to do the job properly. This should mean that, from now on, mere KM testing for blood and only primary transfer, external garment evaluation of fibre evidence, if it results in an acquittal, should operate to defeat any future section 76 application based upon a later more thorough examination.
The point I derive from this is that, now that well informed scientists must know that KM testing for blood, however many times it is carried out and however many scientists carry it out, is not going to reveal blood deposits up to 0.5mm x 0.3mm in dimension, it will henceforth be negligent to fail to carry out LPM [Low Power Microscopy] scrutiny of the garment. If a later cold case review utilises LPM examination of a garment and finds blood, an application to quash an acquittal and retry an accused on the fresh findings should fail.
Looking back at the Damilola Taylor case, it is arguable that at least in the case of the blood stain on the trainer which was visible by the naked eye, that if Danny Preddie or Ricky Preddie had been tried in the first trial and acquitted, that an application to quash the acquittal, seeking a retrial on the basis that the blood stain was new evidence would fail because of a lack of diligence on behalf of the scientists in the original investigation.
But what of the second check? If a second check takes place, as recommended by the enquiry and is found to agree with the first examination does that mean we can be confident that there is no blood on the item? The recent findings in the Stephen Lawrence case give us serious concern as to the effectiveness of such an approach. In the Stephen Lawrence case, a jacket LH/5 was examined 6 times by six different scientists from four different organisations, over a period between 1993 and 2008 and the result was always the same no blood. A fibre was found on the jacket, indistinguishable from a garment worn by Stephen Lawrence which appeared to have a component that could be blood in its MSP spectrum. It was only after this fibre was found was the jacket was examined again, re-searched using LPM for a seventh and then eighth time, when blood was found on the jacket, including a stain on the collar. It is arguable that without the fibre evidence, the blood would not have been found.
Einstein is credited as saying that the definition of insanity is to repeat the same experiment over and over and to expect different results. Second, third, fourth and so on checks where the check is precisely the same process as the first examination appears to fall into that category, at least where the searching for blood is concerned. However, checks where the search is undertaken using a different process, such as LPM, or perhaps some other technique that does not rely so much on the human eye appear to be the way forward.
The fact though that so many scientists from so many laboratories failed to find the blood, even as recently as 2008, and that scientists accept the fallibility of the processes, raises the question as to how many cold cases remain cold cases because blood has been missed. Furthermore that the court of appeal has stated that it is willing to consider that the direct actions of the scientists amount to a lack of diligence which could lead to the failure of applications under double jeopardy -even if new evidence was found. Ironically, the key to the outcome of such applications may not be the new evidence at all, but the manner in which it was found.
