Forensic lab errors in hundreds of crime cases
Hundreds of killers and rapists may have escaped justice because of blunders by the government-owned forensic science laboratory that were uncovered by senior police officers reviewing the unsolved murder of Rachel Nickell on Wimbledon Common.
Senior officers believe that in many of those cases DNA samples could have been found and matched to suspects, had the FSS used different techniques that were being used by other privately run laboratories.
They are furious at the failings and have demanded an explanation from the FSS.
The 2,500 cases will be resubmitted for testing, either at the FSS laboratories or at private labs. The FSS says it may find DNA in about 200 of the 2,500 cases but admits this is merely a guess. Hundreds of suspects who have escaped justice as a result of the mistakes are likely to be rearrested and charged if the new tests provide DNA results.
Tony Lake, chief constable of Lincolnshire police and the Association of Chief Police Officers' spokesman on forensic issues, said the cases in which the FSS had failed to find tiny specks of DNA involved the most serious crimes.
"This is about not getting results when it might be expected that there was DNA, rather than getting a result that was wrong.
This type of DNA analysis of tiny amounts of DNA is carried out normally in the most serious crimes. We were not best pleased. We were not impressed. We rely on our forensic providers to have the highest standards."
The failings were uncovered last year, during a review of the 2001 Nickell murder investigation. Ms Nickell was stabbed to death on Wimbledon Common in July 1992. Colin Stagg was acquitted of murder in 1994 after police were criticised for trapping him into a confession.
During a second inquiry into the killing in 2001 the FSS re-examined items recovered from the murder scene.
But in a test known as low copy number (LCN), involving microscopic samples, they missed tiny samples of DNA that had been taken from her body. When Scotland Yard carried out its review of the inquiry last year another forensic laboratory using a different technique discovered the DNA that the FSS had missed.
Mr Lake was asked to carry out a review to establish the scale of the failings. He wrote to all chief constables yesterday asking them to examine their files for any cases between 2000 and 2005 that have not resulted in a conviction, in which small samples were sent to the FSS and returned negative, when a positive result might have been expected.
He said yesterday that after 2005 the standards at the FSS raised no concerns as different techniques were being used.
The Home Office yesterday denied accusations from David Davis, the shadow home secretary, of a cover-up.
A spokeswoman said: "On operational advice from the police, the initial stage of this operation has been kept confidential.
As soon as ministers became aware of this issue, they asked Acpo to undertake an operational review to secure the nature and extent of it and to take remedial action. Acpo is very close to completing that work and has found no evidence that we should be concerned about standards being used today."
Kathy Lee, a spokeswoman for the FSS, said scientists estimated that of the 2,500 cases that needed retesting, around 200 were likely to provide a positive match with a suspect.
But she admitted this was just a guess.
She said the errors had occurred because the rapid advances in technology meant DNA could now be found on tiny residues. "This happened when LCN was in its infancy," she said.