WATERLOO, Ill. (AP) – Authorities are investigating the death of a St. Louis man who was found unconscious in a jail cell in Illinois.

The 39-year-old man was found in a Monroe County Jail cell around 9:30 a.m. Monday. He was transported to a St. Louis County hospital, where he died.

Monroe County authorities hadn’t identified the man as of Tuesday night.

The Monroe County Sheriff’s Department says the man was being held at the jail in Waterloo, Illinois, on “various charges and a warrant for his arrest out of Missouri.”

Authorities say an autopsy was conducted but the man’s cause of death was pending toxicology tests.

Illinois State Police is investigating.