OKLAHOMA CITY (AP) — A lawyer for a white Oklahoma police officer accused of manslaughter in an unarmed black man's death says she was so hyper-focused on the situation that she didn't hear other officers arrive on the scene or even the deadly gunshot she fired from her handgun. Klinger, a former Los Angeles police officer who shot and killed a suspect just four months into the job, interviewed 80 law enforcement officers involved in 113 separate cases where they shot citizens. Videos from a police helicopter and a dashboard camera of the shooting and its aftermath showed Crutcher, who was unarmed, walking away from Shelby with his arms in the air, but the footage does not offer a clear view of when Shelby fired the single shot. Despite the research, Lori Brown, a professor of sociology at Meredith College in Raleigh, North Carolina, said she believes it's dangerous to think a police officer would use auditory exclusion as a possible explanation for killing a man who was not doing anything aggressive. Crutcher's shooting came four months after former Tulsa County volunteer sheriff's deputy Robert Bates was sentenced to four years in prison on a second-degree manslaughter conviction in the 2015 death of an unarmed black man.