Transcript for Police Body Cam Footage Shows Cop Had History of Confusing His Gun and Taser
Back here at home, and to a new development tonight in the case of an Oklahoma reserve deputy, who shot and killed a suspect during a drug operation. He said he thought his gun was his taser. He now faces trial. Tonight, new video of that reserve deputy, and what it might show. Here's ABC's Clayton Sandell. Reporter: A raid on a suspected drug house. What'd I do? Everything. Reporter: In police body camera video obtained by "The frontier news," you can see former Tulsa county reserve deputy Robert bates, as he talks to the handcuffed suspect, he is shushed by a fellow deputy. What are you moaning about? What's hurting? What's hurting? Stop. Stop. Reporter: At this point, you can see bates has drawn both his taser and his handgun. Significant, because just three weeks later -- Stop, stop, stop. Stop right there. Reporter: -- Bates would shoot and kill 44-year-old Eric Harris during an undercover sting. Oh, I shot him. I'm sorry. Oh, god. He shot me! Reporter: Bates says he confused his gun and his taser. First and foremost, let me apologize to the family of Eric Harris. Reporter: Attorneys for the Harris family say bates, a wealthy local businessman, was too cozy with the former sheriff, Stanley Glanz, lacked required training, and that this latest video proves he should never have been serving Al alongside sworn cops. It's completely unnecessary for Mr. Bates to be wielding a taser, let alone a handgun. Reporter: The former sheriff and the department declined to comment today. Next month,bates goes on trial for manslaughter. He's pleaded not guilty. David?
This transcript has been automatically generated and may not be 100% accurate.