Police investigating Philip's death came across up to 50 envelopes in the actor's home, containing what they believed was heroin, CNN reports. Authorities also found several empty bags which were believed to have contained the class A drug along with prescription drugs, used syringes and other bags containing white powder.
The late actor, 46, who died of an apparent drug overdose, was found in the bathroom of his New York apartment on Sunday by close friend David Katz and the actor's personal assistant Isabella Wing-Davey.
Philip Seymour Hoffman
The New York medical examiner's office is conducting an autopsy on Monday to determine Philip's death. Results could take several weeks to come through.
Investigators are also trying find out where Philip had obtained the drugs from, which could involve searching his phone, and whether anyone was with him at the time of his death. The actor was reportedly seen withdrawing a large amount of money from a cash machine near his apartment, and handing it over to two men in exchange for small bags on the night before his death.
The Oscar-winning star, who won Best Actor for his role in Capote, was due to pick up the three children he had with partner Mimi O'Donnell on Sunday morning. When Philip didn't show up, Mimi reportedly called David to check up on the actor. David and personal assistant Isabella then went to Philip's apartment where they found his body.
The Hollywood star had previously revealed that he had struggled with drug addiction since his student days. Last May, Philip checked into rehab after 23 years of sobriety, according to TMZ.
Fans pay tribute to the late actor outside his New York home
His family has issued a statement, thanking fans for their support at this difficult time.
"We are devastated by the loss of our beloved Phil and appreciate the outpouring of love and support we have received from everyone," the statement read. "This is a tragic and sudden loss and we ask that you respect our privacy during this time of grieving."
Celebrities and fans paid tribute to the late actor on social media sites, while various stars have paid their respects to Mimi and her family in person.
Cate Blanchett and Justin Theroux were spotted visiting Mimi's apartment, where she lives with the couple's three children, on separate occasions on Monday.