More tests ordered on body of dead spy

The decomposing remains of Gareth Williams, 30, were apparently found by police stuffed inside a holdall in the bath of his London home.

Officers broke down the door after attempts by the Foreign Office to locate him via his former landlady failed.

A Home Office pathologist failed to find a cause of death following a post-mortem examination of Mr Williams’ body.

Further tests, including toxicological analysis of his blood for evidence of drugs and alcohol, will now take place.

Investigators from the Met’s homicide and serious crime command have labelled the death as “suspicious and unexplained”.

Sources said there was no evidence Mr Williams had been stabbed, contradicting earlier reports.

Forensic officers have spent two days scouring Mr Williams’ top-floor flat in Alderney Street, Pimlico, for clues as to what happened in his final hours.

Originally from Holyhead, North Wales, he was on secondment to MI6 from his job as a communications officer at the GCHQ “listening post” in Cheltenham, Gloucestershire.

Relative William Hughes said he had no idea of Mr Williams’ line of work.

He told the BBC: “He worked for GCHQ for many years. I knew he was working in London doing something. He would never talk about his work and it felt rude to ask, really.”

Mr Hughes said Mr Williams was “very, very talented”, adding that he had not yet spoken to the dead man’s parents.

The Foreign Office contacted his former landlady Jenny Elliott on Monday after his work colleagues reported not seeing him for “some time”.

Mrs Elliott said he had lived in a flat attached to her Cheltenham property for 10 years and was preparing to return on September 3.

She described him as “a lovely guy, very friendly, very well-mannered and polite and no trouble at all”.

She added: “He was often away. He went to America to work a lot and often combined it with holiday because he hated flying.”

Mr Williams’ London neighbours expressed their shock following the grisly find.

They described him as “extremely friendly”, athletic, a keen cyclist and as having a strong Welsh accent.

Secretary Laura Houghton, 30, said: “His windows were always shut and curtains were often closed. I could never tell if anyone was in. It was strange that we never saw him come and go. I just assumed he worked away.”

Mr Williams joined St Catharine’s College at Cambridge University to undertake a postgraduate certificate in mathematics in 2000 but dropped out a year later.

Sources close to the inquiry said it is not clear how he died and played down speculation that the murder is linked to his secretive line of work.

One source said: “The suggestion there is terrorism or national security links to this case is pretty low down the list of probabilities.”

The Alderney Street flat is about half a mile from the riverside headquarters of MI6, the Secret Intelligence Service.

Residents of the prestigious street include former home secretaries Michael Howard and Lord Brittan.

The flat is in a freehold block whose ownership is hidden behind the private company New Rodina, registered in the British Virgin Islands.

The word rodina means “motherland” in Russian and Bulgarian while public documents revealed current and former residents also have links to Cheltenham.

One Frenchman who lived at the same flat between 2005 and 2006 is an expert in global satellite positioning, radio communications and high sensitivity antennae.

It is the first suspicious death on British soil of someone linked to the secret services since the poisoning of former KGB agent Alexander Litvinenko in 2006.

A GCHQ spokesman said last night: “We have nothing to add.”