Recently, James, a researcher on BBC1’s The One Show, telephoned to ask if I’d be prepared to talk about DNA and the national DNA database.
This is one of those perennial requests that I get – largely, I think, because I take what some regard an “odd” position. I can see both sides of the argument. While I’m suspicious of the DNA of innocent people being kept permanently on the oldest and largest DNA database in the world, I also know through working with serious offenders just how often it is that DNA evidence proves to be their downfall and becomes the mechanism to bring justice to victims – often women who have reported rape.
I explained this to James and we danced around the question of a fee – given re-arranging the school run, travelling to London and getting back home.
We agreed to leave all that to my agent and discussed DNA in light of proposals being put forward by the Home Office in response to recent European rulings, but which would still see the DNA profile of innocent adults being held for six years and slightly different arrangements being introduced for those under 18.
I suggested that we need to move towards the Scottish position, where DNA profiles must be destroyed if the individual is neither charged nor convicted, unless the suspect was prosecuted for a violent or sexual offence. This is a far more proportionate way of dealing with DNA profiles.
Nevertheless, in England and Wales, the DNA database provides some 3,500 matches to crime scenes every month. Between
2007-2008 DNA profiles were used to solve
83 murder cases, 184 rapes and a further 15,000 crimes.
James asked for my thoughts about the fact that our DNA database – depending on which figures are used – seems to hold the profiles of almost 40 per cent of the black men in the country, compared with 9 per cent of white men. I suggested this is not the “fault” of the national DNA database, but reflects the racism that is endemic in our police, courts and sentencing – and which has a cumulative effect resulting in the over-representation of black men on the database. There is even evidence to suggest that some police force areas were deliberately arresting young black men so as to have their DNA taken and stored.
What James didn’t ask about was the real area of controversy in relation to DNA – Low Copy Number (LCN) and its use in court cases. In 1999, scientists developed this technique, which means it is now theoretically possible for them to develop a profile from a single cell (the human body has something like 50 trillion cells in the body), as opposed to a usual sample which would have at least a nanogram of material.
This tiny LCN sample needs to be amplified to produce a profile and this is done through copying the material through a 34-cycle process, during which it is chemically treated so markers become coloured and then displayed as peaks along a DNA graph. The graph is then interpreted.
But there are problems – both with random data when this technique is used and which makes identification impossible; when there are “mixed profiles” (when the sample contains the DNA of more than one person); or where the there are doubts about how the sample has been stored.
It is rare for such doubts to be expressed in court. Simply suggesting that “forensic science” evidence is to be presented seems to suggest to a jury certainty, truth and even – in the wake of the police drama CSI – glamour. I’ve seen juries so blinded by the science that they seem to leave common sense back at their hotel.
No one mentions that LCN is not accepted as evidence in most European countries or in the United States and that the forensic value and reliability of LCN is constantly called into question.
The case against Sean Hoey –charged with the Omagh bombing in 1998 – collapsed in December 2007, largely because it was solely based on LCN evidence. So worried was the forensic science regulator about LCN that he commissioned a report about its value from Professor Brian Caddy of Strathclyde University.
Caddy reported in April 2008 and recommended that the Forensic Science Service should quantify the amount of DNA material available in any case – which they have now done since 2009 – and that there should be national agreements about how LCN DNA profiles are interpreted.
Matters were further complicated as a result of two appeals before the Court of Appeal in December 2009 – the first a murder case in which two brothers, David and Terry Reed, had been convicted, and then a case of sexual assault involving Neil Garmson, who was convicted of disturbing a couple having sex in their car and then forcing the woman to perform oral sex.
These two appeals were dismissed by Lord Justice Thomas, Mr Justice Kitchin and Mr Justice Holroyde, who concluded that LCN was admissible in court and that challenges to the validity of LCN should no longer be allowed if the amount of DNA was above a specified level – a picogram, or a trillionth of a gram.
This does seem extraordinary and Garmson’s case in particular continues to make me feel uneasy. He was not identified by either the victim or her boyfriend, who both described the attacker as having long hair. Garmson was almost bald at the time, which led the Crown to suggest that he had been wearing a wig. The LCN DNA profile that was produced – and on which he was convicted – could have been read entirely differently so as to exonerate Garmson completely. If the Court of Appeal had been hoping to put the controversy of LCN to bed based on the judgement in the Garmson case, it failed spectacularly.
I would have said all of this on The One Show, but I got a call from my agent advising me that they had, in effect, said: “Thanks, but no thanks”. Could it have been the request for a fee or my rather “odd” position?
David Wilson is professor of criminology and criminal justice at Birmingham City University
