Real Death is Not So Simple

It has been a summer of blood-spatter, maggots, stray pubic hairs and all the other bits of forensic detail that make the CSI: Crime Scene Investigation drama franchise such a gruesome hit. Several times a week on Channel Five you can watch while teams of people in plastic romper suits swarm over taped-off murder sites before bearing their grisly finds back to base. There unfeasibly beautiful lab rats - all flicky hair and perilously tight T-shirts - get to work with their microscopes and their test tubes to set about constructing a narrative that explains just how someone almost got away with murder.

The point is - and it is repeated again and again by the lantern-jawed men who head up the CSI teams in Las Vegas, Miami and New York - that the evidence never lies. Suspects may fib and bluff, witnesses will flounder, victims - if they are still alive - send the police haring in the wrong direction. But those blood spatters, bullet casings, maggots and amputated body parts cannot be bought or bullied or made to change their story. Silently at first, but then building to a shout, they bear witness to the way that the crime "went down".

CSI is a show for our post-9/11 times (the head of the New York team, played by Gary Sinise, is even supposed to have lost his wife in the disaster). It has no truck with ambiguity, grey areas or moral relativity. Parallel possibilities of how the crime might have occurred are played out for the viewer before being crisply undercut by the scientific evidence. Smooth-tongued cons and plausible witnesses can only gasp as their cleverly constructed stories crumble in the face of a bullet casing or a stray bit of fibre banged down on the interrogation table by the CSI technicians.

This is a new kind of crime drama for a new kind of world. Law & Order, the cop-and-courtroom series often scheduled alongside CSI, is saturated with a different kind of sensibility, one that looks back to the 1990s, when it first ran. The detective work is slow and haphazard, depending on hunches, favours and luck. The courtroom sequences revolve around two narrative versions of what happened being pitted against one another, leaving the jury - fallible, worried, uncertain - to decide which story, on balance, it believes. The prosecution is headed by Jack McCoy, played by Sam Waterston, whose face is etched with the moral ambiguities of every case. The best one can hope for, his hangdog expression seems to say, is the realisation that we are all, in some way, guilty of creating the society in which these terrible crimes were allowed to flourish.

There are no such worries for the scientist-detectives at CSI. The evidence slices through uncertainty, doubt, ambiguity. If you are an accomplice there will be sand under your toenails to say so. If you are innocent there will be a discarded McDonald's cardboard cup smeared with your DNA to clear your name. There are good guys and there are bad guys and, luckily, there is also a fail-safe way of sorting the one from the other.

But all that looks about to change. New Scientist recently reported that CSI had been found guilty of distorting the criminal-justice system. According to Peter Bull, a forensic sedimentologist from Oxford University, "jurors who watch CSI believe that those scenarios, where forensic scientists are always right, are really what happens". What Bull, along with his scientific colleagues, knows is that real scientific detection is never exact or speedy. Real crime labs deal in percentages and probabilities rather than moral - or narrative - certainties. As a result jurors, primed by the misrepresentation of science on CSI, have become impatient and unbelieving with the complex and far-from-conclusive evidence set before them. It is an odd irony that a programme based on the premise that science leaves no place for the criminal to hide could become responsible for letting bad guys walk.