MORE DETAILS HAVE EMERGED about the personality and private life of Gareth Williams, 30, an MI6 worker found dead inside a sports bag in his flat.

Police found the decomposed remains after Williams’ colleagues reported they hadn’t seen him for 10 days.

Investigators believe he may have been dead for up to two weeks, and will carry out more toxicology tests in their attempt to determine the cause of death. A post-mortem held earlier this week proved inconclusive.

The investigation will include examinations of Williams’s mobile phone and Sim cards found at the scene, as well as his financial records and as CCTV cameras in operation on the streets near the flat.

Williams’ parents returned from a holiday in the US and Canada to identify their sons remains.

A private person

Family member, William Hughes, described Williams as a very private person, saying he had never known him to bring home a partner or discuss his work:

I knew he worked at GCHQ and he had been working in London but I didn’t know what he did. It wasn’t said that we shouldn’t talk about it, I simply never asked and he never told me.

He said that he didn’t know what his nephew did for a living, but believe he was very talented.

Dylan Parry, a childhood friend of Williams, described him as “the kind of person who found it difficult to engage with people on a normal level.”

Gareth Williams had completed his A-level maths and computer science exams by the age of 13. His old maths teacher said:

He was the best logician and the pupil with the fastest brain I have ever met. You only had to say things once, that’s why he was so successful. He could understand things immediately.

In June 2001, Williams dropped out his Cambridge masters course in advanced mathematics after failing an exam, and shortly afterwards began working at GCHQ in Cheltenham. GCHQ is the British government’s listening and communications branch of the security service. 5,500 people work there.

Cycling fanatic

A neighbour of the Williams’ family in Anglesey, north Wales, said that Gareth was a fitness fanatic who particularly enyjoyed cycling:

Gareth was a smashing lad and really into his cycling. His father was called ‘Mr Fitness’ round here because he was a keep-fit fanatic. I don’t even think either of them drank. I think they were teetotal.

Gareth and his dad used to cycle round here together, in Lycra kit and helmets.

A cyclist at the Holyhead cycling club of which Williams was a member for over a decade, said he “wasn’t a great conversationalist” and that no one at the club had spoken to him about his employment or his personal life.