Gareth Williams

Status:

Open

Jurisdiction:

metropolitan-police

Death Location:

Pimlico, London

Summary:

Gareth Wyn Williams was a Welsh mathematician and Junior Analyst for Government Communications Headquarters (GCHQ) on secondment to the Secret Intelligence Service (SIS or MI6) who was found dead in suspicious circumstances in Pimlico, London, on 23 August 2010, at a flat used to house Security Service's staff. The inquest found that his death was "unnatural and likely to have been criminally mediated." A subsequent Metropolitan Police re-investigation concluded that Williams's death was "probably an accident".

Vital Statistics

Circumstances of Death:

Williams was last seen alive on CCTV around 14th August 2010. His laptop was logged on to a cycling website in the early hours of 16th August, after which he disappeared. His disappearance was noted when he failed to turn up for a meeting at MI6 on 16 August 2010. Police visited Williams's home during the afternoon of Monday 23 August 2010, as a "welfare check" after colleagues noted he had been out of contact for several days. His naked, decomposing remains were found in the bath of the main bedroom's en-suite bathroom, inside a red sports bag that was padlocked from the outside, with the keys inside the bag. The local police had gained entry into the top floor flat at 36 Alderney Street, Pimlico at around 16:48; on examination of the bag, the premises were declared a crime scene. Williams's date of death was estimated to have been in the early hours of 16 August, one week before he was found.

Additional Details:

The coroner was critical of SIS for failing to report Williams missing for seven days, which caused extra anguish and suffering for his family, and led to the loss of forensic evidence. The coroner concluded that another party placed the bag containing Williams into the bath, and on the balance of probabilities locked the bag. The coroner said that Williams was probably alive when he was put in the bag and that he probably died shortly afterwards from CO2 poisoning or from a short-acting poison. Evidence at the inquest showed that it would have been virtually impossible for Williams to have locked himself in the bag. Two experts were unable to lock themselves in a similar bag despite making 400 attempts to do so, although one stated there was a small chance Williams had managed the feat. A subsequent Metropolitan Police re-investigation concluded that Williams's death was "probably an accident". The coroner was highly critical of the Metropolitan Police's Counter Terrorism Command (SO15), who failed to tell the senior investigating officer before the inquest began of the existence of nine memory sticks and other property in Williams's SIS office. Williams was buried at Ynys Wen cemetery in Valley, Anglesey, on 26 September 2010, following a private funeral service at Bethel Chapel in Holyhead attended by his family, friends, former colleagues in the intelligence services, and also by the head of SIS, Sir John Sawers.

Case Last Updated:

May 11, 2026