A northwest suburban man on probation for drug possession charges is accused of selling heroin to undercover detectives.

Keith A. Knigge, 40, was arrested Thursday following an undercover operation during which he sold heroin to Lake County Sheriff’s Gang Task Force officers multiple times, according to a statement from the sheriff’s office.

Knigge, of Ingleside, was charged with four counts of unlawful possession of a controlled substance with intent to deliver and one count of unlawful possession of a controlled substance, all felonies, the sheriff’s office said. He was on probation for a February drug possession charge at the time of his arrest.

He remains held at the Lake County Jail on $100,000 bail, the sheriff’s office said. His next court date was scheduled for July 5.

“The members of the Lake County Sheriff’s Gang Task Force will continue identifying and arresting drug dealers throughout the county,” Sheriff Mark Curran said in a statement. “We must continue working together as a community to suppress the heroin epidemic we are facing.”