BIDDEFORD — A Biddeford sex offender was charged Monday with selling his own prescription medication.

Michael J. McKeown, 49, of 111 May St. was arrested by Maine Drug Enforcement agents and charged with aggravated trafficking of a scheduled drug.

The charge was increased to aggravated drug trafficking because McKeown lives across from an athletic field designated as a safe zone by the city.

McKeown allegedly sold drugs to an undercover agent and resisted arrest when agents and Biddeford police arrived at his home at 5 p.m. Monday, according to Steve McCausland, spokesman for the Maine Department of Public Safety.

McKeown is on the Maine Sex Offender Registry and is prohibited from having contact with teenagers. Biddeford police are investigating reports that he allowed teenage boys to smoke marijuana at his house, McCausland said.

McKeown was taken to York County Jail in lieu of $75,000 bail. He is expected to make his first court appearance Wednesday.