Police baffled after all-clear in dead spy drug tests

No evidence of drugs, alcohol or poisons was found during a battery of tests conducted by toxicologists, sources close to the inquiry said.

The 30-year-old GCHQ code-breaker's naked and decomposing body was found in a padlocked holdall in the bath of his Pimlico flat on August 23.

The mysterious circumstances of Mr Williams' death sparked an international frenzy of speculation at the time.

Coroner Dr Paul Knapman is due to review the case in private next Wednesday after opening an inquest on September 1.

Yesterday, a Metropolitan Police spokesman said: "There are no plans to carry out any further tests of this type, but enquiries continue to try and establish a formal cause of death. Mr Williams' death remains suspicious and unexplained and enquiries into the circumstances continue."

Scotland Yard detectives have been hunting for a man and a woman seen calling at the communal door of his Alderney Street home.

Witnesses said the Mediterranean couple, aged in their twenties, were let into the property late on an evening in June or July.

The spokesman said: "The police are still keen for the couple to come forward, or receive any information regarding them from members of the public."