TULSA, Okla. (AP) - A judge is scheduled to sentence a former Oklahoma volunteer sheriff's deputy who was convicted of second-degree manslaughter in the fatal shooting of an unarmed suspect last year.

Tulsa County jurors who found 74-year-old Robert Bates guilty of second-degree manslaughter last month recommended that he serve four years in prison. Bates says he mistook his handgun for his stun gun when he fatally shot Eric Harris. 

A judge is scheduled to sentence the wealthy insurance executive on Tuesday afternoon. 

Harris was restrained and unarmed when he was shot during an illegal gun sales sting. 

His killing prompted a grand jury investigation of the sheriff's office and the indictment and resignation of Sheriff Stanley Glanz, a close friend of Bates.