Chicago (AFP) – A white police officer in the southern city of Tulsa, Oklahoma, has been acquitted of manslaughter in the fatal shooting of an unarmed African-American man, US news reports said Thursday.

Officer Betty Shelby was charged in September with killing Terence Crutcher, whose car had broken down on a Tulsa street.

A jury deliberated for nine hours before acquitting Shelby, according to a local television station, KFOR-TV.

Shelby said she shot 40-year-old Crutcher because she feared for her life, thinking he was reaching for a gun in his vehicle. Authorities later determined that Crutcher did not have a gun.

Prosecutors argued that Crutcher had not made any aggressive moves, but Shelby’s defense attorneys said he ignored the officer’s commands.

In video footage from a dashboard camera, Crutcher is seen with his hands up, leaning against his car. He is then shot once in the chest by Shelby and falls to the ground.

The shooting, the latest in a string of fatal shootings of unarmed African-Americans by police across the United States, led to protests and an increase in tensions in Tulsa.

Oklahoma Governor Mary Fallin appealed for calm in a statement late Wednesday.

“I ask Oklahomans to respect our criminal justice system and especially the jurors, who heard the evidence from both sides in this case,” Fallin said.

“Those who disagree with the verdict have the right to express their opinions; I just ask that they do so in a peaceful manner. I appeal to Tulsans and others to remain calm.”