A leading scientist cast doubt on claims that key forensic evidence he found in the Stephen Lawrence case was flawed.
Edward Jarman said blood on a jacket owned by one of the black teenager’s alleged killers must have been wet when it left a tiny stain.
The jury has heard that the jacket was not seized from Gary Dobson’s home until two weeks after the killing in April 1993, by which time the blood would have been dry.
Jarman said he could not rule out that it was a loose flake of dried blood that soaked into the jacket during tests which involved spraying the jacket with a fine mist of water—but he doubted it.
Dobson and co-defendant David Norris have pleaded not guilty to murder.
The tiny speck of blood has become the most crucial piece of forensic evidence in the case of the black teenager’s killing, 18 years after he was stabbed to death.
Jarman said it was “implausible” the stain could have got onto the collar other than at the time of the stabbing, or from contact with someone involved “very shortly afterwards”.
Jarman told the court, “The probability that it had not come from Stephen Lawrence... is probably less than one in a billion.”
Samples from 30 other stains and flakes were also tested. One with an incomplete DNA profile had a one in 500 match.
Lawyers for Dobson and Norris claim the forensic evidence could easily have been transferred inadvertently during storage, handling and transportation of the exhibits over the years.
Jarman said, “The collar stain is more likely to be the result of a primary route [direct contact with the blood source] rather than more complex routes.”
The trial continues.