Video footage of Gareth Williams's death scene was shown in a court yesterday, unseen by members of his family who could not bear to view the material, which included shots of a bag with the body of Gareth Williams still inside.
Examination of the red North Face sports holdall also showed traces of the DNA of another person on the zip toggle and the padlock, the inquest into the computer specialist's death was told.
Detective Chief Inspector Jackie Sebire, who led the inquiry into his death, said, "They were two minor components of another contributor's DNA. My thought or my opinion since I went into the scene is that a third party had been involved in the death or by putting the body in the bag."
A graphic impression showed the way 34-year-old Mr Williams was found inside the bag – in a foetal position lying on his back, naked, with his knees raised and arms folded across his chest. The key to the padlock was under his right buttock, making it "incredibly difficult" for him to have reached it in an attempt, somehow, to escape.
In any event, said Det Ch Insp Sebire, "there were no signs that he was trying to get out, no damage to his fingernails or hands, no tear in the lining inside the bag. He was very muscular, he trained regularly. I would at least expect some tearing to the netting. He was very calm; his face was very calm."
An examination of the holdall in court showed that it would have been seemingly impossible for Mr Williams to have locked himself into it and then to move it into a bathtub where it was found, the coroner, Dr Fiona Wilcox, pointed out. Yet, apart from the speck of DNA on the bag, detectives had been perplexed by the lack of signs of a "third party" anywhere else in the MI6 officer's home in Pimlico, south-west London.
The police had found no evidence that attempts had been made to wipe out incriminating evidence.
"There was no sign of the place being cleaned, so there were no signs of bleach to destroy it," said DCI Sabire. "There was no evidence the bag itself had been cleaned or washed down or the lock or handles had been cleaned to remove traces of DNA evidence."
What the police did find in the flat was £20,000 worth of designer clothes for women all "immaculate" and "in pristine condition" and many in tissue paper. Make-up items including nail varnish and eyeshadow that were "all new" and apparently unused were also found alongside wigs wrapped in net packaging, which "appear to be unused", including one Mr Williams had bought on his recent trip to the US.
There was also 26 pairs of boot and shoes, most bearing designer labels such as Christian Louboutin, Stella McCartney, Christian Dior and Chloé, some of which appear to have been worn.
The video footage, taken on the evening of 23 August 2010, when Mr Williams's body was discovered, revealed no sign of a break-in at his home, with cash left in a cupboard and a mobile phone on the living room table. The place was in a pristine condition apart from the bedroom, where a blue toweling dressing gown, which had shown traces of Mr Williams's semen the inquest was told, and a duvet cover had been flung on the floor. The wardrobe door was open and a white shirt, still in its laundry wrapping.
Giving evidence later, Sian Jones, who described herself as a "close friend" of Mr Williams, denied that he was a transvestite. "We talked about all kinds of personal matters. I feel he would have been able to confide in me; I wouldn't have been judgemental," she said.
The inquest continues.