It looks as if Philip Seymour Hoffman's loved ones will have to wait a bit longer for closure.

Autopsy results on the 46-year-old actor, who was found dead in New York City on Feb. 2, have been ruled inconclusive, according to the city's medical examiner's office.

More tests are necessary to determine Hoffman's cause of death, a spokesperson for the office stated Wednesday (Feb. 5). No timetable has yet been set for the required toxicology and other tests to be completed.

The Academy Award winner is believed to have died from an accidental overdose of heroin. He was found in a rented West Village apartment with a syringe in his arm and surrounded by bags of what appeared to be the drug. He had recently separated from his partner of 15 years and mother of his three children, costume designer Mimi O'Donnell.

In other news, four people were reportedly taken into custody Wednesday and questioned about selling drugs to Hoffman. Sources say that at least one of those people had the actor's cellphone number.

Hoffman had previously acknowledged his struggles with addiction. A private funeral is set for Friday (Feb. 7) in New York.