Russian oligarch and Kremlin critic Boris Berezovsky was found lying on his bathroom floor with a piece of material around his neck and the same material on a shower rail, an inquest into his death heard on Thursday.
The 67-year-old was found in his mansion in Ascot, west of London, on Saturday.
A post-mortem examination found his death was consistent with hanging, but toxicology tests are being carried out and it will be several weeks before the results are known.
At the opening of the inquest, Detective Inspector Mark Bissell of Thames Valley Police said Berezovsky was found with a "ligature around his neck and a piece of similar material on the shower rail above him".
Although the post-mortem found no evidence of a violent struggle, Bissell said the involvement of a third party "cannot be completely eliminated as tests remain outstanding".
The inquest at Windsor Coroner's Court was opened and adjourned.
In their first public response to the death, Berezovsky's daughter Anastasia Berezovskaya said Wednesday he was not a "typical parent" but described him as an "extraordinary" man.
Friends have said Berezovsky, who fled to Britain in 2000 and launched verbal attacks on the Kremlin from exile, had become deeply depressed after losing a multi-million-pound court case against fellow British-based Russian oligarch Roman Abramovich last year.