The coroner said the body was discovered on Wednesday and preliminary investigation suggested she had died of natural causes. She was found dead in bed by her mother Iris Frederick.
Police say there are no suspicious circumstances. A post- mortem examination has been conducted, but toxicology tests have not been completed.
Ms Frederick, 39, an actress was Sellers's fourth wife of and inherited the bulk of the actor's pounds 4m fortune. She later married the television personality David Frost - the marriage ending in divorce after 17 months - and Dr Barry Unger, a Los Angeles GP.
Her roles included Henry VIII and his Six Wives (1972) and The Prisoner of Zenda (1979) in which she played opposite her late husband. In 1985 she won nearly dollars 1.5m ( pounds 1m) after a court case in which she alleged that the makers of Trail of the Pink Panther - made after Sellers's death - insulted his memory. The film was released in 1982 and made of previously unreleased out-takes.Reuse content