KGB defector: Russia killed the British spy found in a duffel bag

The death of Gareth Williams, a British spy who was found naked in a padlocked duffel bag in his bathtub, has remained a mystery for five years.

Now a KGB defector says that Russian intelligence was behind the killing, the Independent reports.

A cipher expert for the Government Communications Headquarters (GCHQ), Williams was working for the MI6, the British foreign intelligence agency, when he was killed in his apartment in London in August 2010.

Boris Karpichkov, who used to work for the KGB and rose to the rank of major, told the Daily Mirror that sources in Russia claimed the current foreign intelligence agency in Russia (SVR) was behind the murder.

According to Karpichkov, the SVR tried to force Williams into becoming a double agent as they blackmailed him with the fact that he owned thousands of dollars of women's clothes as well as make-up and wig.

Although police assumed he was a transvestite upon finding the clothes, an expert who used to advise the FBI on search techniques believed Williams used those for his job as a spy.

Karpichkov claimed that after the SVR threatened to out Williams as a transvestite, he let them know he was aware of the identity of a Russian spy inside the GCHQ.

"The SVR then had no alternative but to exterminate him in order to protect their agent inside GCHQ," Karpichkov said.

Claiming Williams had been killed by an untraceable poison introduced in his ear, Karpichkov who lives in the same part of London where Williams used to, said he used to see Russian diplomatic cars in the area, and that he has not seen them since Williams' death.

Williams's death received worldwide coverage and garnered a lot of speculation. A coronor ruled in 2012 that Williams was probably the victim of a "criminally mediated unlawful killing in which poison may have been used," the Independent reported.

The verdict stipulated that it was most likely that Williams was murdered, but mistakes made during the investigation meant no proof was found. That inquest was also marked by accusations of an official cover up.

Police suggestions that came out a year later also caused a lot of controversies. Scotland Yard had previously claimed that Williams probably accidentally locked himself inside the bag and that no one else was in the flat at the time of his death.