Not the full story

Deoxyribonucleic acid '“ the correct name for DNA '“ has been admissible evidence in criminal proceedings since 1986, making it one of the newest legal techniques used by the Crown to date. We all know it as the genetic blueprint or code which is almost '“ and I emphasise that word '“ unique to each individual. But often in a report from a forensic scientist which attempts to explain the evidence, the technical terms are so abstruse as to almost defy understanding by ordinary members of a jury, let alone by highly qualified lawyers.

As we have seen in cases such as R v Angela Cannings [2004] EWCA Crim 1, scientists often seem to speak in a language and use a form of analysis which is virtually impossible for the jury and lawyers to follow. As a result, it can be very difficult to challenge such evidence, save through evidence provided by another expert with similar or greater qualifications. The opportunities for confusion and innocent error are great and a good defence lawyer, faced with the problems of funding an expert from the legal aid coffers, faces an uphill task. When the few experts can be paid more, and probably quicker, by the Crown Prosecution Service or police than legally aided defence lawyers, any solicitor can understand the reluctance of an expert to advise the defence team.

Getting started

The current theory is that the DNA from a sample is based on the DNA of blood relatives and that the chances of two people, unrelated to each other, having the same DNA profile is in terms of 1,000,000 to one against. Logically, this means that there are, at least, six people unrelated to each other who have the same DNA in the whole world. However, like all science, any assertion of accuracy to this degree should be explained in ordinary terms to a jury and not blithely accepted by a defence team. I have been told by a DNA expert in the UK that she has come across examples of unrelated suspects with identical DNA '“ something which should be almost impossible in the UK with a population of some 70,000,000.

Note that 'trace' DNA '“ DNA from a small sample found with other DNA samples '“ has now entered the academic and evidential arena. In addition, low copy DNA involves the analysis of very small samples of DNA under analysis. The transfer of DNA, from one person to another or from one place to another, can be quite innocuous. For example, if I shake hands with T in London and T puts his hands onto a train window which travels to, for example, Glasgow, that low copy DNA might appear to put me on that train.

However, DNA is but one tool in the armoury available to the Crown and has been used with increasing frequency in the recent past especially involving serious sexual or violent offences. It is not the be all and end all, but is only part of the Crown case against a defendant. A good defence solicitor should never lose sight of that fact, nor the rule that any scientist is giving an opinion on evidence rather than evidence of a certainty.

The fact of the matter

The question which inevitably arises is what does a defence solicitor have to do to counter the apparently strong evidence which DNA analysis may present against a client? This applies whether the solicitor is acting in connection with a trial or an appeal against conviction when, perhaps, DNA techniques were not available or where the scientific knowledge base has increased since investigation or trial.

The first area is one when a defendant has been charged. The defence solicitors will receive statements dealing with the collection of the samples, transmission to a laboratory and the analysis of the samples by a suitably qualified scientist. Care must be taken to ensure that the samples were properly collected and preserved without the possibility of contamination and this should be checked by careful perusal of the statements together with continuity of the movement of the exhibits. Thereafter, the scientist's report should be read carefully. A scientist is only giving an opinion '“ it is no more than that. If it is to be challenged, the defence solicitor should confirm with the CPS the precise whereabouts of the samples, both evidential and reference samples, identify a defence expert, obtain quotations for the analysis by an independent expert, complete form CDS 5 for prior authority to incur expenses from the Legal Services Commission, and submit the form and wait. Once funding is secured, the experts or the Crown and the defence expert will communicate with each other to arrange for the defence expert to attend a laboratory to analyse the samples and produce an independent report.

Finding the right expert

A solicitor should never forget that an expert is not a hired gun to give an opinion only for the party paying '“ the expert has a duty to be impartial and state an opinion which he or she feels is correct and based upon the evidence. But how does a defence solicitor find a suitable DNA expert? This has taxed many solicitors over the past few years, but I have found that there are a number of academic scientists, frequently undertaking post-doctoral research, who are prepared to undertake scientific analysis at legal aid rates. The legal aid rates are quite low and some experts are balking at being paid on that basis, but they can be found, especially in academia. It pays to ring around various friendly solicitors to find an expert who is prepared to undertake the work at legal aid rates, and who is able to explain the analysis and the results of that analysis in a 'user-friendly' manner. The latter could be vital if and when it becomes necessary to explain complex evidence before a jury, and so the defence advocate can properly cross-examine the Crown expert. In a small criminal defence legal aid firm, it is time consuming to find a suitable defence expert '“ but perseverance can lead to the interests and defence, if any, of the client being advanced and protected.

Once funding has been secured, a good defence lawyer will prepare a complete set of relevant papers for the expert, including all Crown statements relating to the relevant evidence, a copy of any relevant interview given by the client, details of the whereabouts of the Crown samples and the address of the Crown expert, and a brief analysis of the Crown and defence cases to guide the expert to the areas of contention. It is wise to remind the defence expert that the conclusion of any report should be in terms which are as non-technical as possible; this assists the defence solicitor, the client and the advocate who may have to cross-examine a Crown witness based upon the report.

A shield as well as a sword

Unlike estoppel, DNA can be a shield as well as a sword; as has been shown in the case of Sean Hodgson '“ whom I advised and represented before the Court of Appeal [Criminal Division]. DNA was able to show, with as much possibility as scientific knowledge can show, that he was not the murderer, and that, after an exhumation, a totally different person whose DNA match was complete was responsible for the homicide. I advise against leaping on any 'initial' results and advising the client, whether defendant or appellant, that any appeal is bound to succeed. The effect of raising hopes, followed by dashing them if the final report does not support the clients' case, can be imagined and could lead to unfortunate consequences. It is not fair on a client to raise expectations, and initial or preliminary results should be treated as being no more than that. It should only be after receipt of a 'positive' report from the expert that the client should be told of the contents and advised as to its effect and importance.

However, in most cases the client should be advised that the expert's report is but one part of the defence case and that there may be many other aspects of the case put forward by the Crown which must not be ignored. To pin high hopes on one piece of contested evidence is unwise in the extreme. The lesson to be learned from the use of scientific evidence? DNA = Do Not Assume!