(CNN) -- An inmate serving time for assaulting a police officer escaped from an Oklahoma prison Monday, a corrections official said. Mark Dwayne Smith, 28, was last seen at the Jackie Brannon Correction Center in McAlester at 5:30 a.m. Monday, but was discovered missing an hour later during a routine inmate count, state Department of Corrections spokesman Jerry Massie told CNN. Smith had been at the prison since April 2009, serving sentences for assault and battery on a police officer and auto theft, according to Massie. CNN's Tracy Sabo contributed to this report.
Mark Dwayne Smith, 28, was last seen early Monday . He was serving time for assaulting a police officer .