The man charged with nine murders in last year's shooting at a church in South Carolina was assaulted by a fellow inmate in the shower area Thursday morning.

Dylann Roof, 22, was not seriously injured in the assault, and was medically evaluated at the Cannon Detention Center after the 7:45 a.m. incident, said Maj. Eric Watson of the Charleston County Sheriff's Office.

According to the incident report, 25-year-old Dwayne Marion Stafford exited his cell and ran downstairs to the first level of the jail where Roof was preparing to shower. Stafford assaulted him with his hands, hitting him in the face and body. Roof also suffered bruising to his face and back.

No weapons were involved, and detention officers broke up the altercation. The report says the assault was "unprovoked."

Charleston County Sheriff Al Cannon said during a press conference that Roof and his attorneys do not plan to pursue charges, which would have been third-degree assault and misdemeanor battery.

Cannon added that the department is investigating an internal investigation into how Stafford was able to exit his locked cell.

Jail records show Stafford faces charges of strong-arm robbery, first-degree assault and battery and providing false information to a police officer — all cases that are pending. He has been in and out of jail more than a dozen times dating back to 2012.

Roof, who is held in solitary confinement in jail, has been charged with nine murder counts in state court for the shooting attack on Charleston's Emanuel AME Church on June 17, 2015. He is also charged with 33 hate crime counts in federal court, facing the death penalty in both cases.