Gareth Wyn Williams was a 32-year-old Welsh mathematician who worked for GCHQ, part of the Secret Intelligence Service.
He didn't talk much about his job to family and friends, instead choosing to keep the details to himself mainly due to the sensitive nature of his work.
But Williams would soon get forced into the spotlight due to his untimely death.
Williams was found dead in suspicious circumstances at a Security Service safe house in Pimlico, London, on August 23, 2010.
Police arrived at his house that afternoon for a "welfare check" after colleagues had not heard from him for several days. His naked, decomposing body was found in a bathroom, inside a red bag that was locked from the outside.
Police conducted a forensic examination of the apartment and found no sign of forced entry or DNA pointing to someone else being there at the time of his death. Police believe he was dead for about a week before he was found.
But Scotland Yard's inquiry also found no evidence of Williams's fingerprints on the bag's padlock or the bath's rim, which the coroner said suggested that someone else was involved in his death. A key to the padlock was inside the bag, underneath his body.
Williams' family argued that police interfered with DNA that could have helped solve the case, and fingerprints left at the scene were wiped off as part of a cover-up.
Inconclusive fragments of DNA components from at least two people were found on the bag but did not lead to any suspects that police identified publicly.
The coroner reported no injuries on Williams's body and no signs that he had been involved in a struggle. He also tested negative for alcohol and common recreational drugs.
Williams was buried at Ynys Wen Cemetery in Valley, Anglesey, on September 26, 2010, following a private funeral service at Bethel Chapel in Holyhead attended by his family, friends, and former colleagues in the intelligence services.
The Metropolitan Police considered his death "suspicious and unexplained." The FBI also conducted its own investigation into the case.
Authorities have referred to the death as a "neat job", a euphemism for a professional kill. There has been widespread speculation that Williams's death is linked to the secret intelligence work that he was engaged in as a GCHQ officer, but no official link has been created.
Two senior British police sources have said some of Williams's work was focused on Russia, which is known for going after spies who investigate their government.
Coworkers have confirmed that Williams had been helping the U.S. National Security Agency trace international money-laundering routes used by crime groups, including in Moscow.
In 2021, officials confirmed that advances in DNA science would allow the further study of a single hair that was found at the scene of the murder.
A spokesman confirmed to the BBC that a re-examination is under way and detectives are waiting for results on whether they will be able to identify any suspects using the single hair, or if it will turn out to be another dead end in the case that has left Williams's friends and family members will so many questions.
"There is an established review process for investigations whereby new information and, or forensic opportunities are considered," a police official told the news outlet.
