TULSA, Okla. (Reuters) - The white Tulsa police officer who fatally shot an unarmed black man was charged with manslaughter on Thursday and a warrant has been issued for her arrest, Tulsa County District Attorney Stephen Kunzweiler said.

Officer Betty Shelby was charged with first-degree manslaughter for the death of Terence Crutcher, 40. The incident, captured on widely broadcast police videos, is one in a series that has raised questions of racial bias in U.S. policing.

"Although she is charged, she is presumed innocent until a judge or jury determines otherwise," Kunzweiler said. "I don't know why things happen in this world the way they do."

Crutcher, whose car had broken down and was blocking a road, can be seen in two videos provided by Tulsa police on Monday with his hands in clear view before he was shot by Shelby.

A lawyer for Shelby has said she acted because she feared for her life, believing Crutcher was reaching into his vehicle for a weapon during the encounter, which took place last Friday.

Tulsa police have said Crutcher was unarmed and there was no weapon in the vehicle. In a bid for transparency, they released the videos, one of which was taken from a police helicopter and the other from a dashboard camera in a patrol car.

The U.S. Justice Department has launched a separate investigation to see if the officers on the scene violated Crutcher's civil rights.

(Reporting by Lenzy Krehbiel-Burton; Writing Jon Herskovitz; Editing by Chris Reese and Dan Grebler)