AUSTIN, Texas -- A fired Texas corrections officer has his job back after state prison officials determined his friendship on Facebook with an inmate didn't violate policy or raise security concerns.

The sergeant at the Huntsville Unit of the Texas Department of Criminal Justice was reinstated following an internal affairs investigation. The review found several other TDCJ employees, including a top official, had the inmate among their Facebook friends.

The Austin American-Statesman reported Friday the officer contended the inmate was a high school acquaintance and he didn't know the man was in prison.

Agency spokesman Jason Clark says investigators found he had no other relationship and no correspondence with him.

A corrections officer union official says at least three other officers have been disciplined or fired for similar inmate "friends" on Facebook.