An inmate at the State Correctional Institution (SCI) at Mahanoy, Mahanoy Township, Schuylkill County, has been charged with assault for an incident involving another inmate.

Troopers said Nathaniel C. Clark, 30, was charged with two counts each of aggravated assault and simple assault, and one count of harassment. The incident occurred at about 6:58 p.m. May 16.Troopers said prison video captured Clark approaching inmate Michael A. Haynes, 39, from the rear and assaulting him. The video shows that Clark struck/stabbed Haynes in the head, shoulder, and upper back with an unknown type weapon. The video shows Clark striking Haynes about 17 times. Troopers said the assault was unprovoked.Clark was taken into custody by correctional officers and placed in the restricted housing unit. Haynes was treated for injuries in the prison infirmary.The charges were filed at the office of District Judge Anthony Kilker of Shenandoah.