A Suffolk man pleaded guilty in federal court Wednesday to possession of fentanyl with intent to distribute.

According to court documents, Glenn Murphy, 38, sold a total of three ounces of heroin to the Portsmouth Police during an undercover operation, according to a press release from the U.S. Attorney’s Office.

After a subsequent attempt to sell heroin to the police, Murphy was placed under arrest and searched. The police found four baggies containing various drugs, including two baggies containing 78 grams of fentanyl, one baggie containing 12 grams of a fentanyl derivative, and one baggie containing 28 grams of cocaine, according to the press release.

Murphy faces a mandatory minimum penalty of five years in prison and a maximum penalty of 40 years in prison when sentenced on Feb. 12.