By Shavonne Walker

shavonne.walker@salisburypost.com

SALISBURY — The investigation continued Tuesday after a riot at Piedmont Correctional Institution in which as many as 12 people were injured, including four who were stabbed and seriously hurt.

The inmate-on-inmate assault occurred in the prison yard at 2:15 p.m. Monday. The Salisbury Police Department was called in to assist and is jointly investigating with the N.C. Department of Public Safety.

Police officials said no guards were injured, but the prison was placed on lockdown before their arrival.

Police reported that 12 were injured; the prison system reported the number at nine.

Nine inmates were taken for outside medical attention. Eight were treated and returned to the prison. One was admitted to the hospital with non-life-threatening injuries.

The prison remains on lockdown. The Department of Public Safety said Monday there was no timetable for when it would be lifted.

There was no indication that any weapons were brought into the prison from the outside. The weapons used to stab and injure others were devices made inside the prison, said police Detective Travis Shulenberger.