A man is wanted by police for pulling down his pants in front of children in a north suburban forest preserve and offering them money “to change his diaper,” authorities said.

The suspicious incident happened July 11 on the bike trail in the Frank Bobrytzke Preserve between Oakton and Dempster streets in Morton Grove, the Cook County sheriff’s office said in a statement.

A man on a red and black bicycle approached several children between 3 p.m. and 6 p.m., pulled down his pants and “offered the children money to change his diaper,” the sheriff’s office said. The children left unharmed.

A similar incident happened farther north on July 8 on a bike trail near Harms Woods, the sheriff’s office said.

The suspect is a man in his 20s, between 5-foot-10 and 6 feet tall and between 170 and 200 pounds, the sheriff’s office said. He was unshaven and had brown hair. He was wearing a black T-shirt, black jogging pants and black shoes.

Anyone with tips is asked to call Cook County sheriff’s detectives at 708-865-4896.