CNN
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A jury will hear opening statements Thursday in the long-delayed trial of a Colorado man accused of killing 10 people in a Boulder grocery store over three years ago.

Ahmad Al Aliwi Alissa is facing 10 counts of murder, 38 counts of attempted murder and numerous other charges after a judge ruled last year that he was fit to stand trial for the mass shooting at King Soopers on March 22, 2021. He pleaded not guilty by reason of insanity last November, CNN affiliate KMGH reported.

Days before the massacre Alissa was able to purchase a Ruger AR-556, which he used in the killings, after passing a background check, according to court records and the owner of a gun shop in Arvada, Colorado.

The mass shooting occurred in a state familiar with such tragedies, including the 1999 Columbine High School massacre in which 12 students and a teacher were killed and the 2012 Aurora movie theater shooting that claimed 12 lives.

A district court judge in 2021 initially ruled Alissa incompetent to stand trial after he was evaluated by a defense expert, two doctors from a state hospital and a doctor selected by the prosecutors, according to court documents filed by the Boulder County District Attorney’s Office. Doctors determined Alissa’s condition got worse while at the Boulder County Jail. He was later sent to the state hospital for treatment.

Last October, however, the judge found him competent, noting that although Alissa was diagnosed with schizophrenia, evaluations did not show he suffered delusions that would interfere with his ability to stand trial.

Colorado District Court Chief Judge Ingrid Bakke at the time “strongly urged” the Colorado Mental Health Institute in Pueblo to retain him due to the “gravity of this case.” The state hospital granted the request. Alissa had been in the hospital for more than a year before his condition began to improve when he resumed taking his antipsychotic medication, according to Bakke’s order.

On July 30, Bakke granted a defense motion asking that Alissa be returned to the Boulder County jail. His lawyers argued that keeping him in Pueblo would deprive “his ability to understand the nature and object of these proceedings.”

Noting Alissa’s right to “consult with counsel” and “meaningfully participate” in his defense, his attorneys wrote: “The magnitude of this case is plain and obvious.”

CNN has reached out to his defense attorneys for comment.

Families of the victims have grown frustrated with delays in the case, a prosecutor told the court last summer, according to KMGH. And more than three years after the bloodshed, a clear motive continues to elude authorities.

The afternoon of the shooting, Boulder police 911 received multiple calls, according to a court affidavit. One caller told dispatchers the shooter shot out the window of a car and chased a man toward the street. Others said the shooter wore “an armored vest.”

Multiple callers said they were hiding in the grocery store. Employees told dispatchers they “observed the suspect shoot an elderly man in the parking lot. The suspect then walked up to the elderly man, stood over him and shot him multiple additional times,” the affidavit said.

Among the people killed was 51-year-old Boulder police Officer Eric Talley, who was one of the first to respond, former Boulder Police Chief Maris Herold said at the time. Witnesses told dispatchers the shooter fired at police, the affidavit said. Officers had exchanged gunfire with Alissa at the store, according to Herold.

The other victims included store manager Rikki Olds, 25; store employee Denny Stong, 20; store employee Teri Leiker, 51; Neven Stanisic, 23; Tralona “Lonna” Bartkowiak, 49; Suzanne Fountain, 59; Kevin Mahoney, 61; Lynn Murray, 62; and Jody Waters, 65.

Witnesses described the confusion and fight for survival in the grocery aisles. Some shoppers fled through rear doors to the employee area, where workers helped them navigate the unfamiliar space to safety. Others hid in storerooms. One man waiting for a Covid vaccine grabbed his two young daughters and hid in a coat closet. A pharmacy technician took cover under a desk and called her family to say she loved them.

Alissa, by the time he was arrested less than hour after the first 911 calls, had “removed all his clothing and was dressed only in shorts,” according to the affidavit. He sustained a gunshot wound to his upper right thigh.

Alissa’s family emigrated from Syria, his 34-year-old brother, Ali Aliwi Alissa, told CNN at the time. The brother said Alissa was paranoid and often believed he was being followed. The suspect lived most of his life in the United States.