Cook County Jail correctional officer seen punching detainee on surveillance video

CHICAGO (WLS) -- Surveillance video shows the altercation that led to a Cook County Corrections Officer being charged with assaulting a detainee.

We want to warn you, the video can be tough to watch.

Investigators say the video shows Officer Richard Smith and another officer speaking to the detainee in the jail's residential treatment unit.

All of a sudden, Smith appears to attack the detainee, punching him and eventually wrestling him to the ground before other officers race in to stop the incident.

The detainee was treated for his injuries.

Officer Smith is charged with aggravated battery and official misconduct.

The Cook County Sheriff's Office is moving to have Smith fired, too.