By PATTY NIEBERG, THOMAS PEIPERT and COLLEEN SLEVIN

BOULDER, Colo. (AP) — Law enforcement officials and former associates of a 21-year-old accused of killing 10 people at a Colorado supermarket described the suspect as someone prone to sudden rage who was suspended from high school for a sudden attack on a classmate that left the student bloodied.

Ahmad Al Aliwi Alissa, who is from the Denver suburb of Arvada, was booked into jail Tuesday on murder charges a day after the attack at a King Soopers grocery in Boulder. He was due to make a first court appearance Thursday.

Alissa had bought an assault weapon on March 16, six days before the attack, according to an arrest affidavit. Investigators have not established a motive, said Boulder County District Attorney Michael Dougherty. It was not immediately known where the suspect purchased the weapon.

Among the dead was Boulder police Officer Eric Talley, 51, who was the first to arrive after responding to a call about shots fired and someone carrying a gun, said police Chief Maris Herold.

A law enforcement official briefed on the shooting said the suspect’s family told investigators they believed Alissa was suffering some type of mental illness, including delusions. Relatives described times when Alissa told them people were following or chasing him, which they said may have contributed to the violence, the official said. The official was not authorized to speak publicly and spoke to The Associated Press on condition of anonymity.

After the shooting, detectives went to Alissa’s home and found his sister-in-law, who told them that he had been playing around with a weapon she thought looked like a “machine gun” about two days earlier, according to an arrest affidavit.

No one answered the door Tuesday at the Arvada home believed to be owned by the suspect’s father. The two-story house with a three-car garage sits in a relatively new middle- and upper-class neighborhood.

When he was a high school senior in 2018, Alissa was found guilty of assaulting a fellow student in class after knocking him to the floor, then climbing on top of him and punching him in the head several times, according to a police affidavit.

Alissa “got up in classroom, walked over to the victim & ‘cold cocked’ him in the head,” the affidavit read. Alissa complained that the student had made fun of him and called him “racial names” weeks earlier, according to the affidavit. An Arvada police report on the incident said the victim was bloodied and vomiting after the assault. Alissa was suspended from school and sentenced to probation and community service.

One of his former high school wrestling teammates, Angel Hernandez, said Alissa got enraged after losing a match in practice once, letting out a stream of invectives and yelling he would kill everyone. Hernandez said the coach kicked Alissa off the team for the outburst.

“He was one of those guys with a short fuse,” Hernandez said. “Once he gets mad, it’s like something takes over and it’s not him. There is no stopping him at that point.”

Hernandez said Alissa also would act strangely sometimes, turning around suddenly or glancing over his shoulder. “He would say, ‘Did you see that? Did you see that?’” Hernandez recalled. “We wouldn’t see anything. We always thought he was messing with us.”

Arvada police investigated but dropped a separate criminal mischief complaint involving the suspect in 2018, said Detective David Snelling. The man also was cited for speeding in February. “Our community is obviously concerned and upset that the suspect lived here,” Snelling said.

Well after dark Tuesday night, about 100 people mourned at a makeshift memorial near the grocery that was adorned with wreaths, candles, banners reading “#Boulderstrong” and 10 crosses with blue hearts and the victims’ names. Therapy dogs were on hand to provide comfort.

Four young girls huddled in the cold, one of them crying as she reminisced about how they had protested the 2018 shooting at Marjory Stoneman Douglas High School in Parkland, Florida. Others recalled the 1999 massacre at Columbine High School and the 2012 Aurora movie theater massacre.

Homer Talley, 74, described his son Eric as a devoted father who “knew the Lord.” He had seven children, ages 7 to 20.

The other dead were identified 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 Jodi Waters, 65.

Leiker, Olds and Stong worked at the supermarket, former co-worker Jordan Sailas said.

Kim Cordova, president of the United Food and Commercial Workers Local 7, which represents more than 30 store employees, said workers did their best to get customers to safety.

“They grabbed everybody they could and they brought them to the backroom or to other areas of the store to hide or got them out through the back dock,” Cordova said. “And these poor grocery workers have just been through hell in general working through COVID this entire last year of the pandemic.”

Monday’s attack was the seventh mass killing this year in the U.S., following the March 16 shooting that left eight people dead at three Atlanta-area massage businesses, according to a database compiled by the AP, USA Today and Northeastern University.

It follows a lull in mass killings during the coronavirus pandemic in 2020, which had the smallest number of such attacks in eight years, according to the database, which tracks mass killings defined as four or more dead, not including the shooter.

In Washington, President Joe Biden called on Congress to tighten the nation’s gun laws. Senate Majority Leader Chuck Schumer vowed to bring forward two House-passed bills to require expanded background checks for gun buyers. Biden supports the measures, but they face a tougher route to passage in a closely divided Senate with a slim Democratic majority.

___

Associated Press writers Michael Balsamo in Washington, Jim Anderson in Denver and AP staff members from around the U.S. contributed to this report. Nieberg is a corps member for the Associated Press/Report for America Statehouse News Initiative. Report for America is a nonprofit national service program that places journalists in local newsrooms to report on undercovered issues.

By PATTY NIEBERG and THOMAS PEIPERT

BOULDER, Colo. (AP) — A shooting at a crowded Colorado supermarket that killed 10 people, including the first police officer to arrive, sent terrorized shoppers and workers scrambling for safety and stunned a state that has grieved several mass killings. A lone suspect was in custody, authorities said.

Hundreds of police officers from throughout the Denver metropolitan area responded to the Monday afternoon attack, converging on a King Soopers supermarket in a busy shopping plaza in southern Boulder. SWAT officers carrying ballistic shields slowly approached the store as others quickly escorted frightened people away from the building, some of its windows shattered. Customers and employees fled through a back loading dock to safety. Others took refuge in nearby shops.

One suspect was in custody, a tearful Boulder Police Chief Maris Herold said late Monday. Authorities didn’t identify the suspect, though Boulder County District Attorney Michael Dougherty said the suspect was the only person injured and was receiving medical care.

Officers had escorted a shirtless man in handcuffs, blood running down his leg, from the store during the siege. Authorities would not say if he was the suspect. Foothills Hospital in Boulder was treating one person from the shooting scene but refused further comment, said Rich Sheehan, spokesman for Boulder Community Health, which operates the hospital.

“This is a tragedy and a nightmare for Boulder County,” Dougherty said. “These were people going about their day, doing their shopping. I promise the victims and the people of the state of Colorado that we will secure justice.”

Herold identified the slain officer as Eric Talley, 51, who had been with Boulder police since 2010. He was the first to arrive after responding to a call about shots fired and someone carrying a rifle, she said.

“He was by all accounts one of the outstanding officers of the Boulder Police Department, and his life was cut too short,” Dougherty said.

Dozens of police and emergency vehicles, their lights flashing, escorted an ambulance carrying the officer from the shooting scene after nightfall. Some residents stood along the route, their arms raised in salute.

Identities of the other nine victims were not disclosed as police were still notifying their family members.

Dougherty said it was too early to speculate on a motive and that the investigation involving local, state and federal agencies would take days.

The attack in Boulder, about 25 miles (40 kilometers) northwest of Denver and home to the University of Colorado, stunned a state that has seen several mass shootings, including the 1999 Columbine High School massacre and the 2012 Aurora movie theater shooting.

Monday’s midafternoon attack was the seventh mass killing this year in the U.S., following the March 16 shooting that left eight people dead at three Atlanta-area massage businesses, according to a database compiled by The Associated Press, USA Today and Northeastern University.

It follows a lull in mass killings during the pandemic in 2020, which had the smallest number of such attacks in more than a decade, according to the database, which tracks mass killings defined as four or more dead, not including the shooter.

Dean Schiller said he had just left the supermarket when he heard gunshots. He saw three people lying face down — one in a doorway and two in the parking lot. Schiller said he couldn’t tell if they were breathing.

Sarah Moonshadow and her son, Nicolas Edwards, had just bought strawberries when they heard gunfire. Moonshadow told The Denver Post they ducked and “just ran.” Outside, Edwards said, arriving police pulled up next to a body in the parking lot.

“I knew we couldn’t do anything for the guy,” he said. “We had to go.”

Video posted on YouTube showed one person on the floor inside the store and two more outside on the ground. What sounds like two gunshots are heard at the beginning of the video.

Investigators had just started sorting through the crime scene and conducting witness interviews, Dougherty said. Matthew Kirsch, the acting U.S. attorney for Colorado, pledged that “the full weight of federal law enforcement” will support the investigation. He said investigators from the Bureau of Alcohol, Tobacco, Firearms and Explosives were at the crime scene, along with FBI agents.

White House press secretary Jen Psaki tweeted that President Joe Biden had been briefed on the shooting. Gov. Jared Polis, meanwhile, said in a statement that “Today we saw the face of evil. I am grieving with my community and all Coloradans.” The King Soopers chain said in a statement that it was offering prayers and support “to our associates, customers, and the first responders who so bravely responded to this tragic situation.”

___

Associated Press writers Colleen Slevin and Jim Anderson in Denver contributed. Nieberg is a corps member for the Associated Press/Report for America Statehouse News Initiative. Report for America is a nonprofit national service program that places journalists in local newsrooms to report on undercovered issues.