Philip Seymour Hoffman's autopsy 'inconclusive'

Actor Philip Seymour Hoffman's autopsy was inconclusive, the New York Medical Examiner's office said Wednesday.

"We are awaiting the results of further tests," spokeswoman Julie Bolcer told Al Jazeera.

The announcement came a day after four people were arrested in connection with drugs found at Hoffman's home following his death of an apparent heroin overdose, media, including The New York Times, reported, citing unidentified police sources.

The arrests came during a raid on a building in Manhattan's Chinatown after police traced the heroin believed to have killed the Oscar-winning star, the newspaper reported.

A New York Police Department spokesman declined to confirm to Al Jazeera whether the arrests were in relation to Hoffman’s death, saying that “the investigation is still underway.”

Officers found narcotics at the building in Chinatown and four people were arrested, an NYPD spokesman told Reuters.

A second police spokesman told Reuters on Tuesday evening that heroin found in Hoffman's apartment following his death was not cut or mixed with fentanyl, a synthetic narcotic believed by health authorities to be responsible for scores of overdose deaths in recent months.

"There was no fentanyl found in the drugs," the spokesman told Reuters.

Responding to an emergency 911 call on Sunday, police found the 46-year-old actor on the bathroom floor of his Manhattan apartment.

The officers found Hoffman with a syringe in his arm and recovered plastic bags containing a substance believed to be heroin. Law enforcement sources have told Reuters that he died of an apparent drug overdose.

Hoffman, who is survived by his partner, Mimi O'Donnell, and their three children, had detailed his struggles with substance abuse in the past.

The actor, who won an Academy Award for his portrayal of Truman Capote in the 2006 drama "Capote" and was considered one of the most gifted film stars of his generation, had sought treatment last year after more than 20 years of sobriety.

A representative for Hoffman said the actor, who also appeared in such blockbusters as "Twister" and "The Hunger Games," would be buried in a private service, with a memorial planned for later this month.

Al Jazeera and Reuters