Police are reportedly questioning four people currently in custody on drugs charges in connection to sales made to the late actor Philip Seymour Hoffman.

According to a report from CBS News, the NYPD made the arrests earlier this week:

Police had a search warrant for a home in Lower Manhattan, where the arrests were made Tuesday night. The four were being questioned late Tuesday at a local police precinct. Meanwhile, a police official said Tuesday that heroin recovered at the Oscar-winning actor's apartment after he was found there dead with a syringe in his arm has tested negative for the powerful additive fentanyl.

Samples taken from Hoffman's West Village 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.

The actor died on Sunday as a result of a drug overdose. An autopsy began on Monday; results have not yet been revealed. A private funeral is scheduled for Friday in New York City.

Image via Getty Images.