The unexplained death last year in Washington of Mikhail Lesin, a Russian media executive and former adviser to President Vladimir Putin, was accidental and caused partly by alcohol poisoning after days of heavy drinking, US authorities said on Friday.

The death of Lesin, who was found in his hotel room on 5 November 2015, was partly attributable to “acute ethanol intoxication”, according to a statement by city police and the US attorney’s office for the District of Columbia.