U.S. actor Philip Seymour Hoffman was found dead Sunday in his apartment in Greenwich Village, according to The New York Post and The Wall Street Journal in their online editions.

Initial reports indicate that the 46-year-old popular actor, who had admitted having drug problems in the past, may have died from a heroin overdose.

According to the New York Post, Hoffman's body was found around midday on Sunday in the bathroom of his apartment with a syringe still stuck in his arm and the New York Police Department is investigating the incident, while forensic specialists are trying to determine the exact cause of death.

Reports are that investigators found heroin in the apartment.

The actor himself had admitted to the TMZ Web site that - whereas he had been drug-free for 23 years - a year ago he had fallen off the wagon and begun taking pills and sniffing heroin.

Scriptwriter David Katz found Hoffman's lifeless body and called emergency services shortly before noon, sources told The Wall Street Journal.

Hoffman won the Oscar for best male actor for his role as Truman Capote in "Capote" in 2006, and he was nominated for an Academy Award three other times for "Charlie Wilson's War" (2007), "Doubt" (2008) and "The Master" (2012).

The actor and director was born July 23, 1967, in Rochester, New York, and rocketed to fame in the 1990s as one of the best character actors in U.S. film.

Among the other films in which he delivered memorable performances are "Boogie Nights," "Moneyball," "The Hunger Games: Catching Fire" and "Scent of a Woman." EFE