GREENBELT, Md. (AP) — Federal prosecutors say a Maryland man has been sentenced to seven years in federal prison for advertising and distributing heroin on the dark web.

In addition to the prison sentence, the U.S. Attorney’s Office says 44-year-old Russell Ramseur of Largo was given five years of supervised release on Tuesday for conspiracy to distribute and possess with intent to distribute at least one kilogram of heroin and for possession with intent to distribute heroin.

A plea agreement said Ramseur was a registered vendor on a darknet marketplace where he advertised the sale of heroin to the general public and sold up to three kilograms of heroin.