RIVERHEAD - An alleged drug dealer is charged with manslaughter in connection with a fatal overdose for the first time in Suffolk County.

Prosecutors say a form of heroin known as "Aleve" is responsible for causing the overdose deaths of at least 10 people on Long Island. It is a mixture of heroin with a higher-than-usual dose of the synthetic opioid fentanyl.

As previously reported, 29-year-old Roxy Headley Jr., of Mastic, was arrested with nearly two dozen other people last month as part of a long-term investigation.

According to prosecutors, a home on Carlls Path in Deer Park served as a stash house in Headley's drug operation, and the drugs would be resold in places such as Copiague, Amityville and North Babylon.

Suffolk District Attorney Tom Spota says his prosecutor will prove in court that Headley's drugs directly caused the death of one of the 10 overdose victims, a North Babylon man who died in May.

Defense attorney Christopher Gioe maintains his client's innocence and says the manslaughter charge is not viable.

Headley is being held on $10 million bond.

The Nassau district attorney in 2009 charged a suspected dealer with manslaughter. But unlike the Headley case, the dealer in that incident allegedly injected the drug directly into his buyer.