The night law-enforcement officials busted four people, who are believed to have supplied the heroin that killed the 46-year-old actor, reported New York Post online.
Three men - two in their 50s and one in his 20s - and a woman in her 20s had been detained and were being questioned.
They were reportedly arrested in a Chinatown apartment on Mott Street after police received a tip that the drugs found in Hoffman's apartment came from the Chinatown building. Police reportedly found 350 glassine envelopes containing a substance believed to be heroin.
The New York Police Department has also revealed that heroin recovered at Hoffman's apartment has tested negative for powerful additive, fentanyl.
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A friend found the 'Capote' actor dead inside his Manhattan apartment on Sunday with a syringe in his arm.
Investigators recovered more than 50 bags of heroin, along with syringes, a charred spoon and various prescription medications, including a blood pressure drug and a muscle relaxant, law enforcement officials said.
While official toxicology results are forthcoming - they will likely be released next month - preliminary tests of the heroin showed no traces of fentanyl.