The suspect was convicted in 2018 of misdemeanor assault against another student at his high school, and fellow students recall him as having a fierce temper.
The suspect’s identity was previously known to the F.B.I. because he was linked to another individual under investigation by the bureau, according to law enforcement officials.
When he was a senior at Arvada West High School, Mr. Alissa was convicted in 2018 of misdemeanor assault against another student in a classroom, and told the police at the time that it was in retaliation for insults and ethnic taunts. Fellow students recall him as having a fierce temper that would flare in response to setbacks or slights.
Mr. Alissa’s brother described him to the Daily Beast as mentally ill, paranoid and antisocial.
Among the victims of the massacre on Monday was Officer Eric Talley, 51, with the Boulder Police Department, who had responded to a “barrage” of 911 calls about the shooting, Chief Maris Herold said.
The authorities identified the nine additional victims as Denny Stong, 20; Neven Stanisic, 23; Rikki Olds, 25; Tralona Bartkowiak, 49; Suzanne Fountain, 59; Teri Leiker, 51; Kevin Mahoney, 61; Lynn Murray, 62; and Jody Waters, 65.
Chief Herold said at a news conference that police officers had run into the King Soopers grocery store within minutes of the shooting and had shot at the suspect. No other officers were injured during the response, she said. She said Mr. Alissa was taken to a hospital for treatment of a leg injury
Court records show he was born in Syria in 1999, as did a Facebook page that appeared to belong to the suspect, giving his name as Ahmad Al Issa; the page was taken down within an hour of his name being released by the authorities. Michael Dougherty, the Boulder County district attorney, said the suspect had “lived most of his life in the United States.”
The shooting came just six days after another gunman’s deadly shooting spree at massage parlors in the Atlanta area.
“Flags had barely been raised back to full mast after the tragic shooting in Atlanta that claimed eight lives, and now a tragedy here, close to home, at a grocery store that could be any of our neighborhood grocery stores,” Colorado’s governor, Jared Polis, said at the news conference.