Murder suspect David Michael Kalac was charged with attempted first-degree murder for assaulting a jail inmate last month.

He was charged with the assault on Dec. 26.

Port Orchard police reported Kalac, 33, attacked the inmate on Dec. 9. He allegedly used a piece of cardboard to escape his cell and walked to another part of the Kitsap County Jail to enter another inmate’s cell.

Deputy Scott Wilson, spokesman for the Kitsap County Sheriff’s Office, reported that Kalac apparently slid a piece of cardboard between the door and wall to prevent it from locking.

The victim suffered bruises and cuts to the head. Investigators reported the victim was a friend of Amber Lynn Coplin, 30, who Kalac is accused of killing inside a South Kitsap apartment on Nov. 4.

Court documents stated that Kalac pulled the other inmate off his bunk bed and began stomping him, before the man pushed an emergency response button to alert corrections officers of the attack. An officer arrived at the cell and ordered Kalac to stop the assault.

He complied with officer’s command.

The 6-foot-3, 210-pound Kalac was arrested Nov. 5 in Wilsonville, Ore. Coplin’s body was discovered by her son and Kalac posted photographs from the murder scene and made comments on an online chatroom.