Inmate Gary N. Bell collapsed on the floor with multiple stab wounds to the chest. He was pronounced dead by a prison doctor at 1:22 pm.
Bell, 41, was serving a 12-year sentence after being convicted in Sampson County as a habitual felon.
Inmate Edward Wiley confessed to the killing and is charged with first-degree murder. Wiley, 25, is a sex offender currently serving a 15-19 year sentence for statutory rape.
The State Bureau of Investigation and the Scotland County Sheriff's Department are investigating.
More charges against additional inmates are expected to be filed.