If you’re a juror on the Stephen Lawrence retrial, stop reading now…

That ought to do it… Being mindful of the UK’s insanely restrictive laws regarding  sub judice, and what can and cannot be published while a trial is taking place, I’ve held off writing about this, but it now appears that witnesses at the trial have covered similar ground, so I think it’s time everyone else had the same briefing…

Here’s the problem – it doesn’t matter what you think of this particular case, although the mythic status this killing has achieved in the media, as opposed to other crimes, just as bad, does offend me. The race angle skews the whole thing – what other murder is constantly introduced by the BBC as this one is: “the killing of black teenager Stephen Lawrence.” And even 18 years on, the press still colludes in the Met’s cover story – that their original investigation was warped by unwitting racism, rather than the uglier truth: corruption. But I’m not interested in that today. It’s DNA, not race, that is the issue now.

The case has been reopened, and accused men put on trial a second time, because of the Blair government’s scrapping of our ancient prohibition against double jeopardy – legislation that was introduced in direct response to the Lawrence case. Those found innocent or otherwise acquitted at trial can be retried for the same offence if ‘compelling new evidence’  is produced; and in our modern age, that means new or newly uncovered forensic evidence, generally DNA. The problem is that techniques used now to to amplify DNA fragments into identifiable samples  are magnitudes more effective than those used in the past, yet the evidence handling techniques back then were designed to protect only against the possible cross contamination of the day. Put simply,  modern forensic techniques and ancient evidence handling techniques  do not, and cannot, go together.

It’s the central dictum of the various CSIs around on t’telly right now that you change a crime scene and the crime scene changes you – and although this is not reality, the situation with regard to DNA traces is pretty much like that. It’s been said that by using polymerase chain reaction amplification to boost DNA samples one can pick up a trace from an individual if they simply walk through a room. Plonking a set of cable-tie handcuffs on a table in front of a suspect for an hour, then PCRing them for his DNA, as happened to the ‘outback killer‘, Bradley Murdoch, pretty much guarantees a positive sample. But jurors don’t seem to be getting that message – they certainly didn’t in that case.

No, it seems that in high profile trials, like that of  Barry George, the guy framed for killing Jill Dando, jurors still have a touching faith in police and prosecutors – believing that if he’s in dock, well then, he’s almost certainly the guy… My concern is that in the Lawrence case, the same emotional and media power could sway their verdict, even though the former head of forensics in the case has now given evidence, accepting that cross contamination was not only possible, but that he himself had specifically warned of the danger.

Yet he was only warning of the danger once evidence had been gathered, and was in storage – a further danger was that the same officers attended the crime scene, and then visited suspects homes and collected evidence. Never mind evidence of unwitting racism, it is as unwitting vectors for DNA contamination that police offices may be guiltiest.

I don’t blame them – they were not to know. Forensics staff back then were not to know. The evidence gathering and storage process just wasn’t up to the standards necessary to bear this level of investigation. The thing is, today, the CPS knows that. The BBC knows that. The Blair government who introduced this law for political gain knew that. The only question is, does the jury?

The appeal court certainly will.

There are of course other aspects to the trial and no doubt evidence that is strong – nothing I’m saying here should or could, alone, convict or acquit. But it does, in my opinion, mean that the current vogue for reopening cold cases needs to be rethought: the use of DNA evidence, and amplified DNA evidence, from samples that were never expected to yield such evidence, has pitfalls as well as benefits.