Police set to rule out foul play in 'spy in a bag' mystery The naked, decomposing body of Mr Williams, a codebreaker on secondment to MI6 from GCHQ, the signals intelligence agency, was found in a padlocked holdall in the bath of his flat in Pimlico, London, in August 2010. Despite an intensive police investigation, no one has been arrested and the circumstances surrounding his death have remained a mystery. Following an eight-day inquest last year, coroner Dr Fiona Wilcox concluded that Mr Williams was probably "unlawfully killed" in a criminal act after experts found it impossible to climb in to a bag by themselves. She said his death most likely involved a third party and he was either poisoned or suffocated. She also said the possibility that a member of the intelligence services was involved in the maths prodigy's death remained a "legitimate line of inquiry" for police. The Metropolitan Police announced an urgent review of the case in the wake of the inquest findings, including concerns over how some evidence was handled by MI6 and counter - terrorism officers during a two - year investigation in to the death. But it is understood that has now concluded that it was possible for Mr Williams, who the inquest heard had an interest in escapology, to get in to the bag by himself and that was the most likely scenario. A senior Whitehall source said: "It seems as though the coroner made a mistake in ruling out evidence that Williams could not have climbed into the holdall without outside help. If it can be demonstrated that Williams was able to climb into the holdall unassisted, then all the other fanciful conspiracy theories start to fall apart. On behalf of the coroner, two experts tried 400 times to lock themselves into the bag, and one claimed that even Harry Houdini "would have struggled" to squeeze himself inside. But days after the inquest, a retired Army sergeant showed how it was possible to climb into a similar North Face bag and lock it from the inside. The renewed investigation saw officers reinterview MI6 officers and take their DNA samples. However, the Telegraph disclosed last year how detectives increasingly believed Mr Williams probably locked himself inside and died as a result of a tragic accident. Detectives were able to repeat the experiment with some slight differences to the way the bag is locked, which fits with how Williams was found. One source close to the inquiry said at the time: "They have been unable to find any trace of anyone who should not have been in the flat and have every reason to believe that Gareth may have climbed into the bag himself and had been unable to get out."