Dr. Fiona Wilcox, who presided over the inquest in Westminster Coroner's Court, said another person was involved, The Daily Telegraph reported. She described the death as "criminally mediated," and that it was probable "Gareth was killed unlawfully."
Williams, a code breaker for the intelligence agency MI6, was found dead in his apartment in London's Pimlico district in 2010. His body was in the bath in a bag used to hold large sports equipment that was padlocked shut.
His agency did not report him missing for almost a week, which delayed the start of an investigation. Sir John Sawers, head of the British intelligence service, apologized to the family for the delay and said supervisors are now under orders to look into all unexplained absences from work.
Wilcox said the two-year police investigation and seven days of testimony at the inquest have failed to answer questions about the death.
"It is unlikely this death will ever be satisfactorily explained," she said.
Wilcox said she believes Williams was still alive when he was locked in the bag and that he suffocated.
She said there was no convincing evidence he got sexual gratification from being shut into small spaces or that he was interested in bondage. She said he did go to bondage sites on the Internet, but those were a tiny fraction of his computer searches and there was no evidence of searches on claustrophilia.
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