NEW YORK -- Four people arrested on narcotics charges in Manhattan Tuesday night were being questioned by New York City police to determine whether they might be linked to the death of Oscar-winning actor Philip Seymour Hoffman, CBS News has learned.
The New York Police Department confirmed to CBS News that three men and a woman were taken into custody on narcotics possession and other drug charges. WCBS reported that more than 350 bags of heroin were found in three apartments that were searched.
Meanwhile, the NYC medical examiner says Hoffman's preliminary autopsy was inconclusive, and further testing would be needed.
None of the bags had an "Ace of Spades" stamp or marker on them, police told WCBS, as law enforcement officials say some heroin bags recovered from Hoffman's apartment did.
WCBS said it was not clear whether authorities believe the suspects might have sold heroin directly to Hoffman, or to others who did.
Heroin recovered at the actor's apartment after he was found there dead with a syringe in his arm has tested negative for the powerful additive fentanyl, a police official said Tuesday.
Samples taken from Hoffman's Manhattan apartment didn't contain the potent synthetic morphine, which is added to intensify the high and has been linked to 22 suspected overdose deaths in western Pennsylvania, said the official, who wasn't authorized to talk about the evidence and insisted on anonymity.
Investigators also have determined that the "Capote" star made six ATM transactions for a total of $1,200 inside a supermarket near his home the day before his death, law enforcement officials said Tuesday. They've been piecing together his final hours using video surveillance to determine his whereabouts.
The NYC medical examiner completed the autopsy on Hoffman by midday Wednesday, but the cause and manner of death are pending further studies, a source told CBS News senior investigative producer Pat Milton. The source said no likely updates are expected for at least another day or so, and Reuters is reporting that the examiner said "further studies" were needed.
The 46-year-old actor was found dead in the bathroom of his apartment Sunday. His door was double-locked when his body was found around 11:30 a.m. by his assistant and a friend, law enforcement officials have said.
Besides the bank records, investigators discovered buprenorphine, a drug used to treat heroin addiction, at Hoffman's apartment and are examining a computer and two iPads found at the scene for clues, two law enforcement officials said.
A private funeral, limited to family and close friends, will be held Friday in New York, Hoffman's representative said Tuesday. A memorial service is also expected to be held later this month.
"In lieu of flowers, the family requests donations be made in Phil's name to two charities that were very close to his heart: The DreamYard Project and the Christopher and Dana Reeve Foundation. The family wishes to thank everyone for their continued support and good wishes," the actor's publicist, Karen Samfilippo, said in a statement.
Hoffman is survived by his longtime partner, Mimi O'Donnell, and their three children.
A spokeswoman for the medical examiner's office said Tuesday there has been no official determination made on what killed Hoffman. Police have said the medical examiner's ruling on his cause of death will determine whether there is any criminality but they suspect it was an overdose.
More than 50 small plastic envelopes of heroin were recovered in Hoffman's apartment along with syringes, a charred spoon and various prescription medications, including a blood pressure drug and a muscle relaxant, law enforcement officials have said.