AUSTIN, Texas — It was not unusual for Garrett Foster to be at a protest against police brutality on a Saturday night. And it was not out of character for him to be armed as he marched.
Mr. Foster was carrying an AK-47 rifle as he joined a Black Lives Matter demonstration blocks from the State Capitol in Austin, Texas. Gun-rights supporters on both the left and the right often carry rifles at protests in Texas, a state whose liberal gun laws allow it.
Mr. Foster, wearing a black bandanna and a baseball cap, bumped into an independent journalist at the march on Saturday, and he spoke matter-of-factly about the weapon that was draped on a strap in front of him.
“They don’t let us march in the streets anymore, so I got to practice some of our rights,” Mr. Foster told the journalist, Hiram Gilberto Garcia, who was broadcasting the interview live on Periscope. “If I use it against the cops, I’m dead,” he conceded.
Later that night, Mr. Foster was fatally shot, but not by the police. The authorities said he was killed by a motorist who had threatened protesters with his car.
The police and witnesses said the man in the car turned it aggressively toward the marchers, and Mr. Foster then approached it. The driver opened fire, shooting Mr. Foster, who was rushed to a hospital and was later pronounced dead.
The shooting stunned a capital city where demonstrations and marches are a proud and commonplace tradition. By Sunday, Austin police officials had released few details about the shooting or the motive, or whether prosecutors planned to file any charges against the unidentified motorist, who was detained and has been cooperating with the authorities. A GoFundMe page to help Mr. Foster’s relatives with his funeral expenses had already raised nearly $50,000 on Sunday afternoon.
Mr. Garcia, the independent journalist, has filmed numerous Austin demonstrations in recent weeks, and he captured the chaotic moments of the shooting live on video. Protesters are seen marching through an intersection when a car blares its horn. Marchers appear to converge around the car as a man calls out, “Everybody back up.” At that instant, five shots ring out, followed shortly by several more loud bangs that echo through the downtown streets.
Mr. Foster, who had served in the military, was armed, but he was not seeking out trouble at the march, relatives and witnesses told reporters. At the time of the shooting, Mr. Foster was pushing his fiancé through an intersection in her wheelchair.
Mr. Foster and his fiancée, Whitney Mitchell, had been taking part in protests against police brutality in Austin daily since the killing of George Floyd in Minneapolis. Mr. Foster is white, and Ms. Mitchell, who is a quadruple amputee, is African-American. She was not injured in the shooting.
“He was doing it because he feels really strongly about justice and he’s very heavily against police brutality, and he wanted to support his fiancée,” Mr. Foster’s mother, Sheila Foster, said in an interview with “Good Morning America,” adding that she was not surprised he was armed while at the march.
“He does have a license to carry, and he would’ve felt the need to protect himself,” Ms. Foster said.
In Texas, it is lawful to carry rifles, shotguns and other so-called long guns on the street without a permit, as long as the weapons are not brandished in a threatening manner.
The shooting occurred shortly before 10 p.m. at the intersection of Fourth Street and Congress Avenue.
Michael Capochiano, a witness, said he was marching with other demonstrators when he saw a motorist honk his horn and turn toward the crowd, forcing people to scatter.
“You could hear the wheels squealing from hitting the accelerator so fast,” said Mr. Capochiano, 53, a restaurant accountant. “I’m a little surprised that nobody got hit. He was driving at an aggressive speed into the crowd.”
The car came to a stop after turning from Fourth Street onto Congress Avenue and appeared to strike a traffic pylon. As people shouted angrily at the driver, Mr. Foster walked toward the car, with the muzzle of his rifle pointed downward, he said.
“He was not aiming the gun or doing anything aggressive with the gun,” Mr. Capochiano said. “He was not holding it in an aggressive manner.” He added: “I’m not sure if there was much of an exchange of words. It wasn’t like there was any sort of verbal altercations. He wasn’t charging at the car. He was just walking over there.”
Mr. Capochiano, who was standing near the rear of the car, said he saw a handgun emerge from the driver’s window, and he heard multiple shots.
“I saw him go down,” he said of Mr. Foster. “I heard people yelling, ‘He’s got a gun, get down.’ As far as I know, he only shot at the victim. I feel like he was just shooting at that guy.”
David Montgomery reported from Austin and Manny Fernandez from Houston. Bryan Pietsch contributed reporting from Andover, Minn.