Boulder King Soopers mass shooting trial is underway

Opening arguments began Thursday in the trial of Ahmad Al Aliwi Alissa who faces more than 100 charges tied to the fatal 2021 shootings of 10 people , including a police officer, in a Boulder King Soopers.

Why it matters: The long-delayed jury trial focuses less on whether the accused gunman committed the killings and more on whether he was mentally ill at the time.

• The verdict will determine whether Alissa is sentenced to life in prison or sent to a state mental institution indefinitely.

Catch up quick: Alissa, now 25, is accused of opening fire at a Boulder grocery store in March 2021, killing 10 people. He faces 10 counts of first-degree murder.

• He also faces a slew of additional charges for attempted murder and possessing illegal large-capacity gun magazines.
• Alissa was diagnosed with schizophrenia after the shooting. His attorneys are using the state's insanity defense.
• His trial was delayed after experts repeatedly deemed him unfit to understand the legal process or assist in his defense.

The big picture: With the trial underway, prosecutors are tasked with proving to the jury that Alissa intended and planned to kill his victims and that he was well aware his actions were wrong.

What they're saying: "The victims are completely random, but the murders were absolutely planned, deliberate and intentional," Boulder County District Attorney Michael Dougherty told jurors Thursday.

• Alissa began researching mass shootings more than 60 days before carrying out his own, Dougherty said, and looked at more than 6,000 photos of firearms, ammunition and equipment between January and March 2021.
• He also researched "what is the most deadly type of round or bullet," Dougherty said.
• The evidence in the trial, including how he complied with and surrendered to law enforcement, will show Alissa "understood exactly what he was doing was completely wrong and horrific," Dougherty told jurors.

The other side: Defense attorney Samuel Dunn told jurors that Alissa was in the "throes of a psychotic episode" at the time of the shooting.

• "This happened because Mr. Alissa had untreated schizophrenia. This happened because that untreated schizophrenia took the form of screaming voices telling him to commit a mass shooting."
• "The motive, the why" behind the shooting is "insanity," Dunn said.
• "You will hear evidence that the root cause of this was his disease."

What's next: The trial is expected to last three weeks, CPR reports .