A Mills man is accused of attacking an inmate while serving time at the Natrona County Detention Center.

Forty-six year old John Kosmata has pleaded not guilty to one count of aggravated assault.

The Natrona County Sheriff's Office says in early February, deputies at the Natrona County Detention Center found Michael Rollins lying in a pool of blood, with injuries that suggested he was attacked.

According to a report, one laceration was deep enough to see his skull

He was taken to the ICU at the Wyoming Medical Center and put on a ventilator.

Witnesses say Kosmata was angry about other inmates being loud after lights out.

He was arguing with another inmate, when Rollins approached them, insulted Kosmata and then a fight ensued.

After reviewing security camera footage, investigators determined that Kosmata threw the first punch.

At the time of the attack, Kosmata was serving a one year jail sentence in an unrelated case, where he pleaded guilty to two misdemeanor charges of domestic battery.

He is awaiting trial on the aggravated assault charge, and could face up to 10 years in prison if convicted.