The man charged with killing 10 people in a mass shooting at a Colorado supermarket in 2021 was found guilty Monday of 10 counts of murder, according to Suzanne Karrer, chief communications officer for the Colorado Judicial Branch.

Ahmad Al Aliwi Alissa, 25, was charged with 10 counts of murder and a slew of other charges including attempted murder, assault and weapons charges. A jury delivered the ruling after a two-week trial that faced long delays while Alissa's mental health was addressed. He was found competent to stand trial in 2023 after time at a mental hospital.

Not in dispute at trial were the facts of the case: that on March 22, 2021, Alissa opened fire at a Boulder, Colorado, King Soopers grocery store, killing two people in the parking lot and eight people in the store. Alissa pleaded not guilty by reason of insanity and his defense team argued he was so mentally ill at the time that he couldn't tell right from wrong and shouldn't be held legally responsible.

The 10 killed included Eric Talley, Rikki Olds, Denny Stong, Neven Stanisic, Tralona Bartkowiak, Teri Leiker, Suzanne Fountain, Kevin Mahoney, Lynn Murray and Jody Waters. Their ages ranged from 20 to 65. Talley was one of the first police officers to respond to frantic 911 calls, and the other victims included customers and employees of the store.

Alissa's conviction means he will automatically receive a sentence of life imprisonment without parole under Colorado law. The state does not have the death penalty.

The jury found Alissa guilty of all 55 counts against him, Karrer said: 10 counts of first-degree murder, 38 counts of attempted first-degree murder, one count of first-degree assault and six counts of felony possession of a prohibited large-capacity magazine.

Jurors hear testimony from survivors, watch surveillance video of shooting

Authorities have said Alissa began opening fire at about 2:30 p.m. on March 22, 2021, and took just over a minute to kill the majority of his victims. All the people he shot were killed. The shooting ended when Alissa was shot in the leg by a police officer.

Prosecutors said Alissa was deliberate and calculated in his actions during the shooting, and hunted down his victims in an attempt to kill as many people as possible. Jurors heard from investigators, doctors and survivors of the shooting, and saw gruesome surveillance and body camera footage.

Pharmacist Sarah Chen testified that while she was taking cover during the shooting, she heard Alissa say, "This is fun," multiple times.

Assistant District Attorney Ken Kupfner told jurors that Alissa demonstrated a clear intent to kill because he continued to shoot victims who were still moving until they were dead. He also said in closing arguments that Alissa's decision to surrender showed that Alissa knew right from wrong and that his conduct was illegal.

When asked by a doctor after the shooting why he surrendered and stripped down to just his underwear, removing his weapons, armor and clothes, Alissa replied that he did it so he "wouldn't get shot by the cops," Kupfner said.

"He understood his behavior was illegal. He understood it wasn't good behavior to engage in," Kupfner said.

Alissa was armed with a legally purchased Ruger AR-556 pistol, which resembles an AR-15 semiautomatic rifle, about 30 miles (50 km) northwest of Denver, on March 22, 2021, authorities said.

Defense claimed 'insanity is the only explanation for this tragedy'

After the shooting, Alissa was diagnosed with schizophrenia while in custody. He was deemed incompetent to stand trial and underwent treatment, delaying the murder trial. In 2023, Boulder District Court Judge Ingrid Bakke determined he had been restored to competency and that trial could go forward. The decision did not mean he no longer had schizophrenia, but that he was then able to understand the proceedings and participate in his defense.

"Insanity is the only explanation for this tragedy," defense attorney Kathryn Herold said during her closing argument on Friday. "This tragedy was born out of disease, not choice. ... Mr. Alissa committed these crimes because he was psychotic and delusional."

Alissa heard "killing voices" in the moments leading up to the shooting, Herold said. Herold yelled in the court room to demonstrate the yelling voices she said Alissa was hearing. "Kill! Kill! Kill!" she yelled.

Herold told jurors that a verdict of not guilty by reason of insanity would hold the defendant accountable, because it would not imply that he is innocent of committing the shooting. Alissa's defense has never argued he did not carry out the crime.

The trial included testimony from both of Alissa's parents, who told jurors they believed their son was "sick" and that he had been acting strangely before the shooting. Alissa's mother, Khadija Ahidid, said through an interpreter that her son believed he was being followed by the FBI, talked to himself and isolated himself from family beginning in 2019, according to The Associated Press. She said his condition got worse after he got COVID months before the shooting.

"We thought he probably was just possessed by a spirit or something,” Moustafa Alissa, his father, said through an interpreter, AP reported.

Alissa and his family emigrated to the U.S. from Syria when he was a small child, settling in a Denver suburb. His parents and some of his siblings testified that Alissa started becoming withdrawn in high school, acting in a paranoid manner and talking to himself.

Kupfner, one of the prosecutors, said that there is no question that Alissa was mentally ill, but that is not the same thing as insanity, and he was able to distinguish right from wrong.

"We agree he's mentally ill. He has schizophrenia, but he is not insane," Kupfner said.

Contributing: Reuters