CINCINNATI (AP) — A white former police officer on trial for murder testified Tuesday that he feared for his life when he fatally shot an unarmed black motorist during a traffic stop.

Ray Tensing, who was fired by the University of Cincinnati after the July 2015 shooting of Sam DuBose near the campus, also testified that the Confederate flag on the T-shirt he was wearing that day was under his uniform had no meaning to him.

Also Tuesday, an expert defense witness testified that a frame-by-frame analysis of a body cam video shows Tensing was justified in fearing for his life because his body was "violently twisted" during the confrontation.

James Scanlon, co-owner of North American SWAT Training Association, said DuBose made "aggressive, life-threatening action" against Tensing, including turning the steering wheel sharply to the left while the officer's arm was caught inside the car.

Scanlon noted that one of the vehicle's tires narrowly missed running over Tensing's foot — a scenario that has killed some police officers.

Some police officers had testified for the defense Monday that they found Tensing looking shocked and scared after the shooting.

Jurors spent much of Tuesday morning watching video footage of other traffic stops Tensing, now 26, had made before the shooting.

The prosecution rested Monday after a series of state witnesses testified they didn't find any evidence to support Tensing's claim that he was going to be dragged to death as DuBose, 43, tried to drive away.

The university fired Tensing after his 2015 indictment on charges of murder and voluntary manslaughter. The university then restructured its public safety department and made other changes in its policing.

A firearms expert testified for the prosecution that Tensing fired his .40-caliber Sig Sauer service revolver between 1 and 2 feet from DuBose's head, and a deputy coroner said the gunshot severed DuBose's brain stem, causing immediate fatal injury.