No sign of 3rd party in Berezovsky death: UK Police

London: British police on Sunday said they have no evidence to suggest third-party involvement in the death of Boris Berezovsky, the self-exiled Russian tycoon who went from Kremlin kingmaker to fiery critic.

With an investigation underway, police are treating the death of Berezovsky, who fled to Britain in the early 2000s after a bitter falling out with Russian President Vladimir Putin, as unexplained. But the former oligarch survived assassination attempts and recently faced financial difficulties, prompting speculation as to whether his death was part of a conspiracy, or suicide.

Police said on Sunday it would be wrong to speculate on how Berezovsky died pending the results of an autopsy but that they had no reason to suspect.

"We are at the early stages of the investigation and we are retaining an open mind as we progress," said Detective Chief Inspector Kevin Brown. "The investigation team is building a picture of the last days of Berezovsky's life, speaking to close friends and family to gain a better understanding of his state of mind."

Police released some details on the circumstances that triggered their investigation into his demise and a subsequent check for hazardous materials at the property in Ascot, a town 40 kilometres west of London where Berezovsky's body was found on Saturday.

A call came into police from the local ambulance service at 3:23 pm GMT on Saturday saying a man had been found dead, Thames Valley Police said in a statement on Sunday.

The police said an employee of Berezovsky told how he had called an ambulance after becoming concerned for Berezovsky's welfare and forced open a bathroom door locked from the inside to find the tycoon's body on the floor.

The employee was the only person in the house when Berezovsky's body was discovered, police said. Members of the ex-oligarch's family arrived at the home while the paramedic was on scene.

Police explained that after a paramedic declared Berezovsky dead and left the scene, a device measuring his exposure to radiation was triggered, which is why chemical and radiations experts were called to examine the property.

"Officers found nothing of concern in the property and we are now progressing the investigation as normal," a statement from police said earlier, adding that the majority of the cordon put in place around the property has now been lifted.