An MI6 officer whose body was found in a holdall may have been executed by secret agents specialising in the "dark arts", with a cover-up subsequently organised to ensure that his killers did not face justice, a court heard yesterday.
The highly charged allegations came at a coroner's hearing which was also told it was virtually impossible for Gareth Williams to have locked himself inside the bag, but that the hunt for those who may have killed him was sidetracked by a major forensic blunder.
The mix-up, over DNA found on the body, was discovered only two weeks ago – while the investigation into one of the most high-profile spy cases of recent times has been going up a blind alley for the best part of a year.
Westminster Coroner's Court in London was also told that MI6 (the Secret Intelligence Service) had not checked on Mr Williams's whereabouts for more than a week, even though he had failed to turn up for work. As a result, his remains were so decomposed and contaminated that scientists had been unable to ascertain the cause of death.
Anthony O'Toole, representing Mr Williams's relations, told the court: "The impression of the family is that the unknown third party was a member of some agency specialising in the dark arts of the secret services – or evidence has been removed post mortem by experts in the dark arts."
Mr O'Toole said Mr Williams "could have been actively deployed" as an agent up to five months before his death. There was a "bland statement" from MI6 "that the death was nothing to do with his work", said the lawyer. "To properly explore the circumstances of the death, we need to establish the deceased's work," he added.
Mr Williams worked as a cipher and codes expert for GCHQ, the Government listening station, but had been on secondment with MI6 since March 2010. His body was found at his flat in Pimlico, south-west London, in August 2010 in a North Face holdall sealed by a padlock.
Detective Chief Inspector Jackie Sebire told the court that traces of DNA found on one of Mr Williams's hands were previously been regarded as a "key line of inquiry". But it subsequently emerged that "actually the DNA evidence was contamination by a scientist at the scene".
The laboratory responsible, LGC Forensics, last night apologised to Mr Williams's family. "LGC identified the partial profile as matching that of a Metropolitan Police scientist who was involved in the original investigation," a spokeswoman for the company said.
The coroner, Dr Fiona Wilcox, said: "What I am concerned about is that there is a system in placed to detect the error. Human errors will always occur.
"There has been so much public speculation and so much public anxiety that this is the reason the court has to act to address it."
Mr Williams's family, said Mr O'Toole, was concerned a third party who may have been present at his death has still not been traced. There was the DNA evidence which turned out to be contaminated and also, supposedly, a footprint. But both leads had come to "dead ends".
Examination of a door knob which may have provided incriminating material could not be carried out because the expert tasked with doing so found the door had been removed and the knob taken out, said the lawyer.
The inquest into Mr Williams's death, expected to begin in April, will hear from his colleagues at MI6 (who will give evidence anonymously) and GCHQ, toxicology experts, bag experts, as well as from his sister. It will also hear that he may have died after breathing too much carbon dioxide.
Dr Wilcox said she wanted the circumstances of Mr Williams's death to be re-enacted in court. "I want it demonstrated in court how somebody could have got into the bag, done it up and locked it from outside when confined inside. It's the fundamental issue in this case: whether Gareth Williams was able to lock the bag when he was inside."
But Vincent Williams, representing Scotland Yard, held there was no need for such a demonstration. A panel of experts had concluded it "would have been very difficult, if not impossible" for him to lock the bag from the inside.
Timeline: The mysterious death of Gareth Williams
15 Aug 2010
31-year-old Gareth Williams, a cipher and codes expert who worked at the GCHQ listening post in Cheltenham, is seen alive for the last time.
23 Aug 2010
A colleague at GCHQ reports Williams missing. His body is found later that day at his flat in Pimlico, London.
30 Aug 2010
Detectives say they are looking at whether Williams may have been killed by a foreign intelligence agency.
1 Sept 2010
An inquest hears that Williams's remains were discovered padlocked into a sports bag, which was in an empty bath at his flat.
6 Sept 2010
Police appeal for help in tracing a couple of Mediterranean appearance, pictured left, who were seen entering Williams's flat earlier in the summer.
22 Dec 2010
Police reveal that Williams had accessed bondage websites and visited a drag show, amid suggestions that the death could have been the result of a sex game gone wrong.
After 18 months of investigation, police discover that a trace of DNA found on Williams's hand came from a crime scene scientist. They also find that the couple they were tracing were irrelevant to the inquiry.
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