No third party in Berezovsky’s death
A Home Office post-mortem examination is to be carried out.
Mr Berezovsky emigrated to the UK in 2000 after falling out with Russia's President, and was granted asylum in 2003.
"It would be wrong to speculate on the cause of death until the post-mortem has been carried out. We do not have any evidence at this stage to suggest third party involvement," Det Ch Insp Kevin Brown of Thames Valley Police said.
"The investigation team are building a picture of the last days of Mr Berezovsky's life, speaking to close friends and family to gain a better understanding of his state of mind.
"We are acutely aware of the level of interest into his death and are focused on conducting a thorough investigation as we would with any unexplained death."
Mr Berezovsky's body was reportedly found by an employee, who called an ambulance at 15:18 GMT last Saturday.
He had not been seen since around 22.30 GMT the previous evening. — BBC