EDWARDSVILLE, Ill. (AP) — Investigators in southern Illinois say they are concerned about health of a teenage girl and her newborn son who they believe were kidnapped by her stepfather.

Madison County Sheriff John Lakin on Thursday said 13-year-old Katherine Elizabeth Derleth of Carpenter has a congenital heart defect and a pacemaker. She was still under a doctor’s care after having a cesarean section delivery. Equipment to monitor the pacemaker was left behind when she went missing last weekend from a foster home in Madison County

The Belleville News-Democrat reports that police still don’t have any leads in the case.

Authorities on Monday filed kidnapping charges against the stepfather, 39-year-old Christopher M. Derleth of Granite City and were searching for the three. He had been previously ordered not to contact her.