HARTFORD, Conn. (AP) — Two men have pleaded guilty to drug charges connected to a series of overdoses in June that led to three deaths in New Haven.

Fifty-seven-year-old Frank Pina and 48-year-old Steven Whaley pleaded guilty Thursday in federal court in Hartford to possession and distribution of controlled substances.

The two men were arrested within a few days of the overdoses that affected 17 people in New Haven. Authorities say the users believed the substance was cocaine, but an investigation showed it was laced the powerful opioid fentanyl.

Federal prosecutors say Pina supplied drugs to several people who overdosed on June 23 and Whaley was identified as an associate of his who sometimes served as a middleman.

Each man faces a maximum prison term of 20 years at sentencing in the fall.