A post-mortem examination on Russian oligarch Boris Berezovsky has found he was hanged, police said.
The examination by a Home Office pathologist found nothing to indicate a violent struggle, a spokesman for Thames Valley Police said.
Further tests are now due to be carried out on the body of Mr Berezovsky, 67, who was found dead in his country home in Mill Lane, Ascot, Berkshire, on Saturday.
The results of the tests, including toxicology and histology examinations, were likely to take several weeks, police said.
Mr Berezovsky's body was moved from his home and forensic examination of the property is expected to take several days.
Police said they have found no evidence that anyone else was involved in his death, but there has been widespread speculation over what had happened.
Detective Chief Inspector Kevin Brown said: "Scenes of crime officers are carrying out further forensic examinations at the property and these are expected to last several days.
"A cordon will remain in place until this work has been completed, to protect the scene.
"While this important investigative work continues, we are unable to comment on any items found within the property.
"I would like to reiterate that we have no evidence of any third-party involvement at this stage."
Specialist officers in chemical, biological, radiological and nuclear substances examined the country pile on Sunday before declaring it safe.
The search was prompted when a radiation detector worn by the paramedic who pronounced the businessman dead was triggered on leaving the property.
The paramedic's detector, a personal electronic dosimeter (PED), is a health and safety device used routinely by emergency services.
An employee of Mr Berezovsky, believed to be the bodyguard, had called for the ambulance shortly after 3pm on Saturday after forcing open a bathroom door and finding the oligarch dead on the floor.
The employee had not not seen Mr Berezovsky since 10.30pm on Friday and had become concerned for his welfare, according to police.
Officers said they are speaking to the Russian's close friends and family to build up a picture of his state of mind in the last days of his life.
It is thought that he was having serious financial difficulties after paying out astronomical sums in legal fees over the last few years, and wanted to return to Russia.
The oligarch, who last year lost a multi-billion pound High Court battle with Chelsea FC owner Roman Abramovich, could have run up more than £100 million in legal bills since 2011.
In July of that year, he paid out Britain's biggest ever divorce settlement to ex-wife Galina Besharova.
Reports suggested the deal was worth more than £100 million.
And he later built up fees totalling more than £250,000 after becoming embroiled in a case at the High Court with his former partner Elena Gorbunova, who sat at his side throughout much of his battle with Mr Abramovich.
Mr Berezovsky emigrated to the UK in 2000 after falling out with Russian president Vladimir Putin.
In fear of his life, he sought political asylum in the UK and moved to the South East, buying upmarket properties in Knightsbridge, London, and Berkshire.
The businessman survived a number of assassination attempts, including a bomb in his car that decapitated his chauffeur.
He became a vocal and strong critic of Mr Putin's rule in Russia, where he had become a wanted man.
In 2006 the Kremlin accused foreign-based opponents of fatally poisoning former KGB spy-turned-dissident Alexander Litvinenko.
It was thought that Russia was in part referring to Mr Berezovsky, who denied the allegation and accused Mr Putin of personally being behind Mr Litvinenko's death from radioactive polonium-210 poisoning.