A former Oklahoma volunteer sheriff's deputy who said he mistook his handgun for his stun gun when he fatally shot an unarmed suspect last year was convicted of second-degree manslaughter on Wednesday, reports the Associated Press.

Jurors handed down the verdict in the case of 74-year-old Robert Bates, a wealthy insurance executive accused of fatally shooting Eric Harris while working with Tulsa County sheriff's deputies last year during an illegal gun sales sting. Harris, who had run from deputies, was restrained and unarmed when he was shot.

The shooting — which was caught on video — sparked several investigations that, among other things, revealed an internal 2009 memo questioning Bates' qualifications as a volunteer deputy and showed that Bates, a close friend of the sheriff's, had donated thousands of dollars in cash, vehicles and equipment to the agency.

The jury recommended a four-year prison term, the maximum, and Bates was handcuffed and taken into custody pending formal sentencing at a later date.