LITTLE ROCK — The Arkansas State Police Commission on Monday fired a Fort Smith-based state trooper for having sex while on duty.

The commission acted on a recommendation by State Police Director Col. Stan Witt in the case of Trooper Zach Saxon, who was accused of misconduct.

According to Saxon’s investigative file, he and the woman, who is married, had a sexual relationship for several months but had sex only once when he was on duty — at his Fort Smith residence on his lunch break.

Witt’s letter of termination did not state a specific reason, but Saxon was a new recruit and still under probation, and probationary troopers recommended for termination can be fired without cause, according to state police spokesman Bill Sadler.