Dylann Roof, the man accused of carrying out a horrific June 2015 massacre during a Bible study class at the Mother Emanuel African Methodist Episcopal Church in Charleston, was assaulted by another inmate at the South Carolina jail where he is being held, authorities say.

Roof, 22, who was arrested on charges of gunning down nine parishioners at a historically black church in Charleston, was showering at the jail when another inmate left his cell, ran down the stairs and attacked him, according to a Charleston County Sheriff’s office incident report.

The inmate, Dwayne Stafford, 25, struck Roof in the face and body with his hands before officers broke up the fight at the Charleston County Detention Center, according to the report.

Roof suffered bruises to his face and back, but medical staff checked and cleared him, according to the incident report. Stafford will be charged with assault in the third degree, Charleston County Sheriff’s Office Spokesman Major Eric Watson said, adding that an internal investigation has been opened.