Investigators on Tuesday were trying to determine what motivated a 21-year-old man, charged in the shooting at a Boulder, Colo., grocery store, to take the lives of 10 people, in the second mass shooting in the United States in less than a week.
The gunman was armed with both a military-style semiautomatic rifle and a pistol when he walked into the King Soopers store on Monday and opened fire, officials said. They identified the suspect who was arrested at the scene as Ahmad Al Aliwi Alissa, who lived in Arvada, a nearby suburb; he was charged on Tuesday with 10 counts of first-degree murder, which in Colorado carries a penalty of life imprisonment without parole.
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.
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".
