Department spokeswoman Joan Heath says 35-year-old Leeland Mark Braley was found hanging in his cell at a state prison in Jackson at 5:12 a.m. Friday.
Heath declined to release any more details about Braley's death but said it is under investigation.
Braley was sentenced to death in August 1999 for the Sept. 2, 1998 stabbing death of 25-year-old Kelli Hammond, an insurance agent in Zebulon.
According to testimony at Braley's trial, he went into Hammond's business to ask for money. When she refused, he returned with a knife and gun. Prosecutors said Braley cut Hammond's throat and then stabbed her.