RALEIGH, N.C. (AP) - North Carolina prison officials still can't put their finger on how many guards and inmates had been assaulted at an understaffed prison prior to the deadliest attempted prison breakout in state history last month.

A state prison official said Thursday they don't know how many employees or inmates at Pasquotank Correctional Institution have been injured by violence in the past year. Three employees died and one remains gravely injured after the failed breakout three weeks ago.

State prisons spokesman Jerry Higgins said he also had no tally of how many prison workers have been assaulted at other prisons across the state since the Pasquotank attack Oct. 12. At least one corrections officer was attacked by an inmate in that time at North Carolina's main women's prison.