Milwaukee police Dominique Heaggan-Brown, right, sits with Attorney Steven R. Kohn, during Heaggan-Brown's trail in Milwaukee on Wednesday, June 14, 2017. Jurors in Heaggan-Brown's trial who is charged with killing a black man fleeing a traffic stop were expected Wednesday to see footage of the shooting from an officer's body camera. (Michael Sears/Milwaukee Journal-Sentinel via AP)

MILWAUKEE - A former Milwaukee police officer on trial in a fatal shooting that sparked riots in a predominantly black neighbourhood said Friday he will not testify, as his attorneys prepare to begin presenting his defence.

Dominque Heaggan-Brown announced his decision a day after jurors saw bodycam video showing how his fatal encounter with Sylville Smith unfolded in the span of 12 seconds. Smith ran away from a traffic stop and was armed when the foot chase began, but he had thrown his gun over a fence a split second before Heaggan-Brown shot him in the chest last year.

Prosecutors contend Heaggan-Brown shouldn't have fired the shot that killed Smith, while the officer's attorneys maintain he had to react quickly to defend himself.

The Aug. 13 shooting triggered two nights of riots in Milwaukee's Sherman Park neighbourhood where it happened, bringing to the surface the long-simmering tension between black Milwaukee residents and the police department.

But unlike other police shootings that have given rise to a national debate over how officers interact with African-Americans, Smith, 23, and Heaggan-Brown, 25, are both black and from the same neighbourhood where the shooting occurred.

Video from the body cameras of Heaggan-Brown and another officer at the scene have become the focal point of the trial, showing how rapidly the traffic stop escalated. The trial was the first time the videos were shown publicly.

"It happened so quick, like we just," Heaggan-Brown said, snapping his fingers twice as he sat in a police cruiser talking to a supervisor several minutes after the shooting.

On Monday, Heaggan-Brown's defence attorneys plan to call a police trainer to testify about how officers are taught to assume that someone who has a handgun is likely to be armed with another.

Heaggan-Brown has said he thought Smith was reaching for another gun in his waistband when he shot him in the chest. But prosecutors have said during the trial that Heaggan-Brown and other officers on the scene never bothered to check Smith for other firearms after he was killed.

Heaggan-Brown's bodycam video shows him begin chasing Smith immediately after stepping out of his patrol car. The camera shows Heaggan-Brown briefly pointing the gun at Smith as he begins running after him, but puts his gun back in his holster as Smith turns into a path between two houses.

Smith slips and falls near a fence, dropping his gun. He begins reaching for it as he stands up, his left hand holding the fence.

When the video is slowed frame by frame, Smith is seen holding the gun by the barrel to throw it over the fence. Prosecutors argue that shows Smith no longer posed a threat.

The two shots by Heaggan-Brown came in quick succession — within two seconds of each other — striking Smith once in his right arm as he threw away his gun and then in the chest as he hit the ground on his back.

Heaggan-Brown and two other officers had approached Smith's rental car because it was parked more than a foot from the curb, and a man standing by Smith's passenger door led police to believe a drug deal was happening.

Heaggan-Brown faces 60 years in prison if he's convicted of first-degree reckless homicide. He was fired in October after being charged with sexual assault in an unrelated case. He's scheduled to go on trial in that case in August.

News from © The Associated Press, 2017