New York police have reportedly arrested four people as part of an investigation into the suspected heroin overdose death of Philip Seymour Hoffman.

Some 350 bags of heroin were also seized during the arrests in Lower Manhattan, unnamed police officials were quoted by US media as saying.

Philip Seymour Hoffman, 46, was found dead at his Greenwich Village home on Sunday with a syringe in his arm.

Dozens of suspected heroin bags were found near his body.

Some were stamped with the ace of hearts and the ace of spades, which are said to be brand names for heroin that street dealers use.

No definitive cause of death has been given, as police try to piece together his final hours using surveillance video and inspecting computers found in his home.

Police say the heroin found in Hoffman’s apartment was not mixed with the synthetic narcotic fentanyl.

Fentanyl has been blamed for a number of recent overdose deaths.

Philip Seymour Hoffman is reported to have withdrawn a total of $1,200 in six visits to a cash machine the day before his death.

The acting world has been paying tribute to a man described as one of the finest actors of his generation.

Lights along theatre marquees on New York’s Broadway are due to be dimmed later in honor of Philip Seymour Hoffman, who earned three Tony award nominations for his work in theatre work in the city.

Philip Seymour Hoffman, who is survived by his partner Mimi O’Donnell and their three children, has spoken candidly in the past of his struggle against drug addiction.

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According to New York City police, up to 70 bags of suspected heroin have been found inside Philip Seymour Hoffman’s apartment a day after his death.

Philip Seymour Hoffman, 46, was found dead at his Greenwich Village home on Sunday with a syringe in his arm.

A post-mortem examination is expected to be carried out on Monday. Police suspect Philip Seymour Hoffman died of an overdose.

The lights along theatre marquees on New York’s Broadway were to be dimmed on Wednesday in honor of Philip Seymour Hoffman.

Philip Seymour Hoffman earned three Tony award nominations for his work in New York theatre.

The actor is survived by his partner Mimi O’Donnell and their three children. In a statement, his family said: “We are devastated by the loss of our beloved Phil.”

Julia Bolcer, a spokeswoman for the New York City Medical Examiner, said she was unsure when the results of Monday’s post-mortem examination, or autopsy, would be available.

“Sometimes we have to perform additional testing,” she said.

The post-mortem examination could explain how Philip Seymour Hoffman died apparently soon after injecting suspected heroin.

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New details about Philip Seymour Hoffman’s apparent drug overdose emerged Monday.

Philip Seymour Hoffman, 46, was found dead in his New York City apartment just after 11:30 a.m. Sunday – with a hypodermic needle still in his arm.

According to law enforcement sources, authorities at the scene found roughly 50 bags of heroin, numerous syringes, addiction treatment medication, blood pressure medication, and a muscle relaxant.

Officials also discovered a few books about Truman Capote, the legendary author Philip Seymour Hoffman won an Academy Award for playing in the eponymous 2005 film.

Law enforcement officials also said that toxicology tests will likely determine Philip Seymour Hoffman’s cause of death.

A city police lab is testing unused heroin found in the actor’s apartment to determine potency.

It was too soon Monday to know if the heroin Philip Seymour Hoffman injected was tainted, if he mixed levels between two heroin “brands,” or if the actor took too much of the drug.

Authorities also found six bottles of prescription drugs – including the blood pressure medication clonidine hydrochloride; the addiction treatment drug buprenorphine; the attention-deficit disorder treatment drug vyvanse; the anti-anxiety drug hydroxyzine; and the muscle relaxer methocarbamol.

Three of the bottles had a prescription to Philip Seymour Hoffman on them, but the vyvanse, buprenorphine and hydroxyzine did not. It was not immediately clear if the latter three drugs were prescribed to Philip Seymour Hoffman but just not properly labeled.

Philip Seymour Hoffman had spoken openly about past substance abuse battles, saying he quit using drugs and alcohol and “got sober” at 22 years old.

However, in early 2013, Philip Seymour Hoffman checked himself into rehab for 10 days.

At the time, Philip Seymour Hoffman told TMZ that he had begun using prescription medicines, and his use escalated to heroin.

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