Experts say it was almost impossible for a British spy whose naked body was found locked inside a sports bag to have climbed inside and pulled the zipper closed himself- increasingly the likelihood someone else was involved in his mysterious death.
Cryptology expert Gareth Williams, 31, worked for Britain's secret eavesdropping service GCHQ but was attached to the MI6 overseas spy agency when his remains were found in August 2010 inside the bag in a bathtub at his London apartment.
Police are not certain exactly how Williams died and have so far made no arrests, although a senior detective has told an inquest on the spy's death that she believes someone else must have been involved.
Coroner Fiona Wilcox is in charge of the inquest, which must attempt to determine when and how Williams died.
Police have indicated Williams' death may have had links to his private life — possibly during in a sexual encounter gone awry. His relatives, however, insist his demise must be related to his highly secret work.
The inquiry heard earlier this week that MI6 colleagues failed to report Williams as missing for a week, meaning that police lost vital chances to gather evidence at the scene.
The hearing has also been told that Williams had visited websites on sadomasochism and had previously had to call for help after he tied himself to his bed and couldn't escape.
Peter Faulding, an-ex military reservist who specialises in rescuing people from confined spaces, told the hearing Friday that getting into this bag would likely even have defeated famed escapologist Harry Houdini.
"I couldn't say it's impossible, but I think even Houdini would have struggled with this one," Faulding told Westminster Coroner's Court in London. "My conclusion is that Mr Williams was either placed in the bag unconscious, or he was dead before he was in the bag."
Faulding said he had made 300 unsuccessful attempts to lock himself inside an identical sized sports bag, measuring 81 centimetres by 48 centimetres. Williams was the same height as Faulding, 170 centimetres tall.
A second expert, William MacKay, told the hearing that it was possible, but very unlikely, that Williams could have climbed inside the bag and locked it unaided. His yoga-practicing assistant had made more than 100 attempts to recreate the feat without success, MacKay said.
"I would not like to say that it could not be done," MacKay said. "There are people around who can do amazing things and Mr Williams may well have been one of those persons."
My conclusion is that Mr Williams was either placed in the bag unconscious, or he was dead before he was in the bag
The hearing was also told that detectives had found video stored on the spy's mobile phone which appeared to show Williams dressed in only black leather boots and gyrating at a camera.
A trawl of his internet browsing had uncovered searches for bondage sites, designer female clothing and high-profile drag artists.
Wilcox expects to deliver a verdict in the case next Wednesday.