The collapse and death of River Phoenix outside a Sunset Strip club has stunned many in Hollywood’s entertainment industry, where some said the 23-year-old actor was one of the most gifted of his generation.

Phoenix, a star of such films as My Own Private Idaho and Running on Empty, was a teen idol often described as so dedicated to healthy living that he would not eat meat or dairy products or wear leather.

The Los Angeles Coroner’s Office, which conducted an autopsy, said on Monday that it could not determine the cause of Phoenix’s death and that the results of a toxicological analysis for drugs or alcohol would not be available for about six weeks.

The possibility that some substance may have been a factor in Phoenix’s death was raised in the initial 911 emergency call by a man who said he was the actor’s brother.

According to a tape recording, the caller said that Phoenix may have “had Valium or something” before suffering a seizure about an hour before his death.

The actor collapsed about 1 a.m. (4 a.m. EST) Sunday outside a trendy West Hollywood nightclub, The Viper Room, which is partly owned by actor and singer Johnny Depp.

His 1986 coming-of-age film, Stand By Me, instantly established him as an important young actor.

He won an Oscar nomination for Running on Empty, a 1988 film in which he played the son of radicals on the run.

Harrison Ford, who played Phoenix’s father in The Mosquito Coast (1986), and the adult Indiana Jones to the late actor’s younger Jones character in Indiana Jones and the Last Crusade (1989), said he was “terribly sad.”