One of four people held by detectives investigating the death of Philip Seymour Hoffman had the actor’s phone number saved on his mobile.
The 46-year-old actor was found dead at his home, apparently with a needle in his arm.
Police, who suspect a drug overdose as the cause of death, said there were 50 envelopes of heroin, syringes and other pills in the apartment.
However, further tests have been ordered on the body after the results of a post-mortem examination were inconclusive.
Three of the people arrested have been charged with drugs offences.
Robert Vineberg faces a felony charge of heroin possession with intent to sell, while Juliana Luchkiw and Max Rosenblum were charged with a misdemeanor charge of possessing cocaine, not heroin.
A fourth person was released without charge.
A lawyer for Vineberg denied he had any role in Hoffman’s death.
Hoffman was found dead in this apartment block
“This case and the charges against Mr Vineberg have absolutely nothing to do with the death of Philip Seymour Hoffman,” Edward Kratt said.
“We’re hoping the (district attorney) will not use Mr Vineberg as a scapegoat.”
He declined to say whether Vineberg knew Hoffman.
Luchkiw and Rosenbaum had two bags of cocaine, while investigators found about 300 packets of heroin, a bag of cocaine and about $ 1,200 in cash in Vineberg’s apartment, according to criminal complaints.
Luchkiw and Rosenbaum both deny knowing Hoffman.
It was not immediately clear which of the suspects was believed to have Hoffman’s number.
Police are also investigating the withdrawal of about $ 1,200 (£736) in six transactions from a supermarket near the actor’s home the day before his death.
The sudden death of the father of three young children, hailed by many as the finest character actor of his generation, has shocked Hollywood and devastated his family.
US media have reported that Hoffman’s funeral will take place on Friday at St Ignatius of Loyola Catholic Church on Park Avenue, preceded by a private wake the day before.
The actor was shooting the final Hunger Games film when he died
On Wednesday night theatres along Broadway dimmed their marquee lights for one minute at 7.45pm in his honour.
Hoffman had received three Tony Award nominations for his stage work, two best leading actor nods for performances in True West and a 2012 production of Death of a Salesman, and another for best featured actor in 2003’s Long Day’s Journey into Night.
Hundreds of friends and fans, meanwhile, gathered to pay their respects during a candlelight vigil outside the Labyrinth Theater Company, where Hoffman once served as artistic director.
“Phil was a leader in the greatest sense of the word, because he didn’t just talk the talk, he walked the walk,” said actor Eric Bogosian.
“We will more than miss Phil. We will live in a smaller world without him. We all know that for sure. We can only say tonight that we were lucky to know him.”
Fans have laid roses, photographs and beer outside the apartment at 35 Bethune Street where he was found dead, close to the home of his three children and estranged girlfriend Mimi O’Donnell.
According to US media, police said heroin found in Hoffman’s apartment did not contain fentanyl, a powerful additive that has been tied to 22 recent fatal overdoses in Pennsylvania.
Last year Hoffman admitted to falling off the wagon, after two decades of sobriety, starting with prescription pills and escalating to heroin use.
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