21-year-old Ahmad Al Aliwi Alissa was arrested as the suspect in the slayings of ten people at a Boulder, Colorado, supermarket on Tuesday.
After previously naming a police officer who had been killed, authorities also named nine more victims (Denny Strong, 20, Neven Stanisic, 23, Rikki Olds, 25, Talona Bartkowiak, 49, Suzanne Fountain, 59, Teri Leiker, 51, Kevin Mahoney, 61, Lynn Murray, 62, and Jody Waters, 65.)
According to Boulder Police Chief Maris Herold, the victims ranged in age from 20 to 65.
On Monday, the shooting at the crowded supermarket sent terrified shoppers and staff fleeing for their lives, shocking a state and a country that has seen many mass killings.
Officer Eric Talley was killed during a shootout with the suspect inside the store.
According to Boulder County District Attorney Michael Dougherty, the suspect was being treated at a hospital and was scheduled to be booked into the county jail later Tuesday.
Prior to that, authorities only confirmed that a suspect had been apprehended but did not specify if it was the shirtless, light-skinned man with a bloodied leg who had been seen being led out of the King Soopers store in handcuffs.
Investigators are also trying to figure out why the suspect opened fire inside the grocery store. According to Dougherty, the case is still in its early stages, but investigators assume the perpetrator was the sole gunman.
According to a law enforcement official briefed on the incident, the shooter used an AR-15 weapon, a lightweight semi-automatic rifle.
Officials were working quickly to locate the weapon. The official spoke to the Associated Press on the condition of anonymity since he was not allowed to speak publicly.