Transcript for Reserve Officer, 73, Charged in Shooting of Unarmed Black Man
charges revealed late today against a reserve deputy who authorities the say thought he was reaching for his taser and instead pulled out his gun. The unarmed suspect did not survive. Here is the moment just before. The 73-year-old deputy, part of the team chasing this suspect. The suspect running there. The reserve deputy moments later firing the gun. Tonight, authorities say he is charge wd second dedegree manslaughter and you are about to hear what he said right after he fired the gun. Stop right here. Reporter: The moment deputies catch up with suspect Eric Harris on the streets of Tulsa the worst should have been over. Roll on your stomach. Reporter: But this disturbing scene April 2nd was just beginning. Oh, I shot him! I'm sorry. Reporter: That is the voice of 73-year-old volunteer reserve deputy Robert bates apologizing after firing his gun instead of his taser. Oh god he shot me! Reporter: An hour later Harris is dead. Today the district attorney charged bates with second-degree manslaughter. It's a Luger. Reporter: Harris ran from police after allegedly selling a gun to an under cover Tulsa deputy. Tonight, Harris' family is speaking out. He's hollering for help and there is no aid. You see the blood out his side. 6. Reporter: He warned his colleagues before pulling the trigger and dropping the pistol, not expecting the powerful recoil of the gun. He knew that he errored. No one intended for Mr. Harris to day that die. Departments in all 50 states rely on reserve officers who work with full time cops. Bates, a businessman,s with more than qualified to be on the street. In addition to the charge, the FBI is going to investigate civil rights violations. The justice department is monitoring the case. Clayson Sandell, thank you for the breaking developments. And tonight, the race for president.
This transcript has been automatically generated and may not be 100% accurate.