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Hoffman, a known addict, was found dead in his New York apartment with a hypodermic needle reportedly in his arm around bags of marked "Ace of Hearts" and "Ace of Spades."
Those types of heroin are often laced with fentanyl, an opiate used by cancer patients and a mixture blamed for dozens of deaths in recent weeks.
Police are "looking at if (Hoffman) had the bad batch going around," an unnamed source told Fox News.
Fentanyl-laced heroin killed 22 people in Pennsylvania last week. Maryland, New York, and Ohio have also seen surges of overdoses linked to the deadly drug in the past year, according to the Pittsburgh Post-Gazette.
Police and health officials have also been watching a new strain of fentanyl-laced heroin that has shown up in different parts of the U.S. This specific derivative of fentanyl, called "acetyl fentanyl," has been linked to dozens of overdose deaths in the past several months.
The Centers for Disease Control and Prevention warned Americans about the acetyl fentanyl trend in August.
Ten acetyl fentanyl overdoses in Rhode Island last year were the first documented cases of the synthetic opioid showing up in illegal drugs, and more possible cases have popped up in other states since the CDC issued its initial warning. Cases have been confirmed in Pennsylvania and Louisiana, and authorities in Massachusetts are worried that some recent overdose deaths there are linked to the deadly synthetic.
Acetyl fentanyl is a man-made version of the painkiller fentanyl and isn't available on the prescription market. The CDC notes that it's up to five times more potent than heroin.
People who are buying drugs laced with acetyl fentanyl might have no idea that they're not getting what's marketed to them, increasing the chance of overdose and death.