Mystery over couple who visited ‘spy in bag’ case flat

Detectives say they have failed to trace the "Mediterranean couple" who visited the flat — owned by the intelligence services — in June or July despite appeals for them to come forward.

They believe the couple, in their thirties, were known to Mr Williams as neighbours do not recall buzzing them into the address. Detectives believe they could be significant to the inquiry.

The body of the GCHQ codebreaker and maths genius was found inside a zipped and padlocked North Face hold-all three weeks ago today.

The bag had been placed inside the flat's ensuite bath and may have been there for up to eight days. Police have been baffled by the death because there were no signs of violence, and toxicology tests showed Mr Williams had not taken drugs or alcohol. There were also no signs of a struggle or a forced entry at the flat in Alderney Street and nothing appeared to have been stolen.

Tests are unable to suggest if Mr Williams was dead or alive when he entered the bag. Reports that the

5ft 8in Mr Williams could have closed the padlock around the two zip handles from inside the bag have been played down by detectives, who have been unable to find a method for doing it.

They view it as extremely unlikely that he padlocked the bag himself.

That suggests Mr Williams was either forced into it against his ill, co-operated with a second party in a possible sex game or was already dead when he was placed inside the holdall.

The results of further tests for the possible presence of a rare toxin are being awaited. Police do not believe the mystery couple is the same as one Mr Williams met regularly at Patisserie Valerie in Holland Park, who were not Mediterranean in appearance.

Anyone with information should call 020 8358 0200, or Crimestoppers anonymously on 0800 555 111.