Police rule out foul play over Russian supergrass found dying outside his Surrey mansion

But cause of death not pinpointed despite two post mortem examinations

A Russian millionaire and supergrass found dying outside his Surrey mansion did not die in suspicious circumstances, police said yesterday.

Surrey Police said that after a " lengthy investigation" it had found no evidence of foul play in the death of Alexander Perepilichnyy, a wealthy businessman who was linked to the Sergei Magnitsky affair as a potential witness in the corruption scandal involving Russian officials.

But the force said a cause of death had not been pinpointed despite extensive testing and two post mortem examinations on the body of Mr Perepilichnyy, who had returned from Paris on the day of his death in November last year following meetings with fellow Russians.

Associates of Mr Perepilichnyy said he had been warned that his name appeared on a hit list drawn up by a criminal gang in Moscow.

Detectives were criticised after it took three weeks to order toxicology tests on Mr Perepilichnyy's body, a delay which experts said could have made obtaining evidence of any role play by poisonous substances in his death more difficult.

In a statement, Detective Chief Inspector Ian Pollard, who led the investigation, said: "I am satisfied that following extensive enquiries, including a post mortem examination by a Home Office pathologist and a full and detailed range of toxicology tests, there is no evidence to suggest that there was any third party involvement in Mr Perepilichnyy's death."

The death of the businessman, who is thought to have been running at the time of his death outside his home on a private estate in Weybridge, will now be the subject of an inquest.

Dominic Raab, the Conservative MP for Esher and Walton, told The Independent: "Whether or not the delay in initiating toxicology reports prejudiced the outcome, we remain no closer to the truth of what happened to Mr Perepilichnyy.

"Though there may not be any positive evidence of foul play, there is no evidence that he died of natural causes and there was a wealth of circumstantial evidence that his life may have been under threat."