Three white men charged with murder in the US state of Georgia made a series of impulsive "driveway decisions" that led to the death of an innocent Black jogger, the prosecution said Friday at the opening of the high-profile case.

Gregory McMichael, 65, his son Travis, 35, and their neighbor William "Roddie" Bryan, 52, are on trial for the February 2020 shooting of 25-year-old Ahmaud Arbery.

The three men contend they mistook Arbery, who was out for a jog, for a burglar in their neighborhood of Satilla Shores and invoked a Georgia law allowing ordinary citizens to make arrests.

Prosecutor Linda Dunikoski dismissed those claims in opening arguments on Friday 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.

"All three of 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. Or mentioned the crime they actually said (Arbery) committed," she said.

The prosecutor said the defendants "didn't simply follow Mr. Arbery in their truck."

"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 pickup trucks for five minutes until he was "trapped like a rat," Dunikoski said, using a description that Gregory McMichael told 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 cellphone.

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.

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.

Arbery became one of the symbols of countrywide "Black Lives Matter" protests against racial injustice and police violence.

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.

Prosecutors challenged the defense strikes of eight of the potential Black jurors but the judge found the defense attorneys had presented valid reasons for their exclusion.

"They've been able to explain to the court why, separate from race, those individuals were, in fact, struck from the panel," Walmsley said.

Local prosecutors, for whom Gregory McMichael, a retired police officer, 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.