The central London flat where the body of Gareth Williams was discovered in Aug 2010.
An inquest has been opened into the mysterious death of a British spy whose naked body was found padlocked in a bag at his home two years ago.
The decomposing remains of Gareth Williams, 30, were found in August 2010 in a holdall in the bath at his London home, near the headquarters of Britain's MI6 external intelligence service where he worked.
His family believe secret agents versed in the "dark arts" tried to cover up his death, but Scotland Yard detectives have found no evidence that anyone else had been with Williams in his flat at the time of his death.
Around 30 witnesses are expected to give evidence in the five-day inquest at Westminster Coroner's Court in London.
Four intelligence agents among the witnesses were granted anonymity after coroner Fiona Wilcox said "there will be a real risk of harm" to national security and international relations if their identities are revealed.
Anthony O'Toole, a lawyer for Williams' relatives, told Wilcox at a pre-inquest review hearing last month that the family believe someone else was either present when he died, or broke into his home afterwards to destroy evidence.
"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," he said.
Williams, believed to be a mathematics genius, was just days from completing a one-year secondment at MI6 from his job at GCHQ, Britain's electronic "listening post" which monitors communications for intelligence purposes.