Actor Philip Seymour Hoffman died of a toxic mix of drugs, including heroin, cocaine and other drugs, the New York City medical examiner's office told the hollywoodreporter.com.

The development ended a month-long mystery about the cause of Hoffman's death, initially assumed to be a heroin overdose, as he was found with a needle sticking out of his arm on the bathroom floor of his apartment here.

The police found several envelopes of heroin, used and unused syringes and various prescription drugs at his residence.

According to reports, investigators found more than 20 used syringes in a plastic cup and bags containing white powder.

An initial autopsy on the Oscar-winning actor, performed shortly after he was found dead on Feb 2, was inconclusive, which meant that further tests, including a toxicology study, would need to be done to determine the cause and manner of his death.

The results of those tests show that Hoffman had also ingested cocaine and other drugs.

The actor, who was laid to rest Feb 7, is survived by three children - Tallulah, Cooper and Willa, whom he had with his longtime partner, costume designer Mimi O'Donnell.