BOULDER, Colo. (AP) — The suspect in the Colorado supermarket shootings bought a gun before the shooting at a local gun store after passing a background check, the store’s owner said Friday.

John Mark Eagleton, owner of Eagles Nest Armory in the Denver suburb of Arvada, said in a statement that his store was cooperating with authorities as they investigate the Monday shooting that killed 10 people, including a police officer.

Eagleton said the suspect in the shooting, Ahmad Al Aliwi Alissa, passed a background check conducted by the Colorado Bureau of Investigation before purchasing the firearm.

Authorities previously said Alissa, 21, purchased the AR-15 style gun used in the mass shooting on March 16, six days before Monday’s fatal shootings. Alissa is from Arvada.

“We are absolutely shocked by what happened and our hearts are broken for the victims and families that are left behind. Ensuring every sale that occurs at our shop is lawful, has always been and will always remain the highest priority for our business,” Eagleton said in the statement.

The statement added: “Regarding the firearm in question, a background check of the purchaser was conducted as required by Colorado law and approval for the sale was provided by the Colorado Bureau of Investigation. We have and will continue to fully cooperate with law enforcement as their investigation continues.”

Alissa was convicted in 2018 of misdemeanor assault after he knocked a fellow high school student to the floor, climbed on top of him and punched him in the head several times, according to police documents. He was sentenced to probation and community service.

Colorado has a universal background check law covering almost all gun sales, but misdemeanor convictions generally do not prevent people from purchasing weapons. If Alissa had been convicted of a felony, his gun purchase would’ve been prohibited under federal law.

According to the arrest affidavit, Alissa bought a Ruger AR-556 pistol — which resembles an AR-15 rifle with a slightly shorter stock.

According to two law enforcement officials, Alissa was born in Syria in 1999, emigrated to the U.S. as a toddler and later became a U.S. citizen. He would need to be a citizen to buy a gun. The officials were not authorized to speak publicly and spoke to The Associated Press on condition of anonymity.

An AR-15-style gun recovered inside the supermarket was believed to have been used in the attack, said a law enforcement official briefed on the shooting who was not authorized to speak publicly and spoke to the AP on condition of anonymity.

Alissa made his first court appearance Thursday. His public defender asked for the mental health evaluation but provided no details about Alissa’s mental health.

The suspect’s next hearing will not be scheduled for two to three months to allow his defense team to evaluate his mental state and evidence collected by investigators.

He is charged with 10 counts of first degree murder and one count of attempted murder for allegedly shooting at a police officer who was not hurt. Among those slain was Boulder Police Officer Eric Talley, 51, who was the first officer to arrive on the scene, according to Boulder police Chief Maris Herold.

Alissa entered court in a wheelchair, presumably because of a gunshot wound to the leg that he suffered in an exchange of gunfire with police at the King Soopers grocery.

Before his court hearing, Alissa was last seen handcuffed and being led out of the supermarket by police on Monday. He had removed all clothing except his shorts before being taken into custody, and his leg was bloody.

A rifle, a green tactical vest and a handgun were recovered inside the grocery store, according to the arrest affidavit.

Alissa was treated at a hospital before police transferred him — using Talley’s own handcuffs — to the Boulder County Jail. Police said they made sure to tell Alissa the handcuffs on his wrists were Talley’s.

Alissa has since been moved to a jail outside Boulder County due to safety concerns stemming from threats made against him that jail staff became aware of, Boulder County sheriff’s spokeswoman Carrie Haverfield said in a statement Friday.

Alissa did not enter a plea, which will come later in the judicial process, and is jailed without bail.

Talley’s funeral has been scheduled for Tuesday in the Boulder County city of Lafayette. Talley, who joined the police department in 2010, had seven children.

Anderson reported from Denver. Associated Press writers Brady McCoombs and Lindsay Whitehurst in Salt Lake City, Michael Balsamo and Colleen Long in Washington 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.