ST. CHARLES, Mo. (AP) — Charges have been filed against the parents of a 2-year-old St. Charles County boy found dead after he was left alone while his parents used methamphetamine.

Twenty-five-year-old Lucas Russell Barnes and 22-year-old Kathleen Peacock were charged after an autopsy determined their son died of hyperthermia, or overheating. He was found dead Sunday.

St. Charles County Prosecutor Tim Lohmar said Tuesday that Barnes and Peacock are charged with felony child abuse and manufacture of methamphetamine in a residence with a child present.

Lohmar says the child was left for 38 hours in a room with a space heater that had no thermostat to determine when it got too hot. He says the parents were using methamphetamine during that time.

It’s unclear if they have lawyers.