Washington (AFP) - Opening arguments began on Friday in the trial of three white men charged with murdering a Black jogger with prosecutors saying they had no valid reason to pursue him and defense attorneys claiming they were just trying to make a "citizen's arrest."

Gregory McMichael, 65, a retired police officer, his son Travis, 35, and their neighbor William "Roddie" Bryan, 52, are facing murder and other charges for the February 2020 shooting of 25-year-old Ahmaud Arbery.

A graphic video of the shooting of the unarmed Arbery went viral on social media and added fuel to last year's protests against racial injustice sparked by the murder of George Floyd, a 46-year-old African-American man, by a white police officer in Minneapolis, Minnesota.

The three defendants contend they mistook Arbery for a burglar in their Georgia neighborhood of Satilla Shores and invoked a since-repealed state law that allows ordinary citizens to make arrests.

Prosecutor Linda Dunikoski dismissed those claims and walked the jury, made up of 11 white people and a single Black person, through the events that led to Arbery's death.

The McMichaels, who were armed with a shotgun and a handgun, and Bryan chased Arbery in their pickup trucks through their neighborhood based on "assumptions and driveway decisions," Dunikoski said.

"These defendants did everything they did based on assumptions," she said. "They made decisions in their driveways based on those assumptions that took a young man's life."

The prosecutor said the three men had no reason on the day of the shooting to suspect that Arbery, an avid jogger, had committed any crime as he ran past their homes.

"There's absolutely no evidence in this case that anyone was making an arrest," Dunikoski said. "No one said 'I was making a citizen's arrest today.' No one said that."

The defendants "didn't simply follow Mr. Arbery in their truck," she said.

"Gregory McMichael and Travis McMichael sought to confront Mr. Arbery and took their guns with them to do it," she said.

At one point, Gregory McMichael shouted "Stop or I'll blow your fucking head off" at the fleeing Arbery, the prosecutor said.

'Trapped like a rat'

Arbery was chased by the men in their trucks for five minutes until he was "trapped like a rat," Dunikoski said, using a description that Gregory McMichael gave police.

"This was an attack on Mr. Arbery for five minutes and the only thing Mr. Arbery did was to run away," she said.

The jury was shown video of Gregory and Travis McMichael following Arbery in a pickup truck and Bryan chasing them in his own vehicle and filming the scene on his cell phone. 

At one point, Arbery attempts to run around the front of the McMichaels' stopped truck.

Travis McMichael, who had gotten out of the vehicle, opens fire with a 12-gauge shotgun. A wounded Arbery is seen struggling with McMichael before being killed by another blast.

Bob Rubin, a defense attorney for Travis McMichael, said the father and son pair had reason to believe Arbery was the person suspected of repeatedly going into a house under construction on their block and stealing items from a boat moored there.

"They’re going to try to detain him for the police," Rubin said. "This is what the law allows. A private person may arrest an offender."

Travis McMichael took his shotgun with him for "self-protection," Rubin said.

As Arbery rounded the front of the vehicle he "is on Travis such that Travis has no choice but to fire his weapon in self-defense," the defense attorney said. "It's his life or Ahmaud Arbery's life.

"It's tragic that Ahmaud Arbery lost his life but at that point Travis McMichael is acting in self-defense," Rubin said.

During more than two weeks of jury selection, defense attorneys for the three white defendants eliminated 11 of 12 prospective Black jurors, prompting accusations of racial discrimination.

Superior Court Judge Timothy Walmsley said there "appears to be intentional discrimination" in the composition of the jury but that he would allow the trial to proceed anyway.

About 25 percent of the 85,000 residents of Glynn County, where the trial is taking place, are Black.

Local prosecutors, for whom former police officer Gregory McMichael had worked for a long time, did not make any arrests in the case for nearly three months.

It was only after the video of the shooting was leaked online that the case was transferred to state police and charges were filed.