ROCKFORD, Ill. (WTVO) — An investigation has been launched following the death of an inmate at the Winnebago County Jail.

The Illinois State Police Division of Criminal Investigation Zone 2 Winnebago Boone Integrity Task Force launched the investigation at the request of the Winnebago County Sheriff’s Office.

Winnebago County Correctional Officers found Christian K. Littrell, 44, unresponsive in his personal cell around 9 p.m. Tuesday, according to ISP. He had been booked into jail on Sunday for DUI. Lifesaving efforts were performed on scene and Littrell was transported to the hospital, where he was pronounced dead.

An investigation is ongoing.