The jury in the Betty Shelby manslaughter trial reached a verdict after nine hours of deliberation.
Shelby is charged with killing Terence Crutcher in September.
An Oklahoma jury began deliberations on Wednesday in the manslaughter trial of a white Tulsa police officer who fatally shot an unarmed black man in an incident caught on video that stoked the debate over racial bias in USA policing.
During a trial in Tulsa, Betty Shelby, 43, said she had shot Terence Crutcher, 40, because she feared he was reaching for a gun in his auto during a routine traffic matter last September.
She said Crutcher put his hands on the SUV and then moved to reach into the vehicle.
"I'm told in my training that you don't let them pull their arm back out. they can pull out guns and kill you", Shelby said under questioning by her attorneys, according to the Tulsa World.
Prosecutors have said there was no reason for Shelby to fire on a man who was walking away from her.
Shelby's attorneys argued that in the two minutes before cameras began recording the encounter, Shelby repeatedly ordered Crutcher to stop walking away from her and get on the ground.More news: Google Avoids Genericide, Will Remain A Protected Trademark
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Assistant District Attorney Kevin Gray argued that even if Shelby followed her police training, which taught her that "action beats reaction", it doesn't mean she didn't commit a crime. Crutcher can be seen with his hands in the air.
Shelby stopped after seeing Crutcher, a 40-year-old father of four, in the middle of a road on September 16, opening fire after he refused commands to lie down.
Crutcher ignored her order - and also ignored orders from her and another officer, Tyler Turnbough, who arrived on the scene, Shelby said.
McMurray says Shelby is ready to get back to her life. An officer in a helicopter hovering above Shelby and Crutcher was overheard saying Crutcher "looks like a bad dude" who "could be on something".
Crutcher's family said police attempted to "demonise" Crutcher over the drug possession to deflect attention from the fact officers didn't find a gun inside his SUV.
Gray asked Shelby why she didn't initially mention in her interrogation interview that Crutcher smelled like chemicals associated with PCP.
Prosecutors asked Shelby on cross-examination why she, too, didn't use a Taser rather than a gun. She said she had forgotten that detail at the time. Rights advocates saw the Crutcher case as another in a string of deaths of unarmed black men at the hands of the police in the United States that has spawned periodic protests and the Black Lives Matter movement. The 12-member jury consists of three African-American jurors after an African-American alternate juror replaced an Asian juror who fell ill on Monday.