Witness testifies gunman said "This is fun!" during shooting at grocery store

Witness testimony continues as people inside a King Soopers store in Boulder took the stand and described what they saw and heard on March 22, 2021 . Ahmad Alissa is accused of shooting and killing 10 people , including Boulder Police Officer Eric Talley.

On Thursday, pharmacist Sara Chan described what she heard inside the store that day, "I heard yelling. At first, I couldn't hear what he was saying but then I listened more closely."

She continued, "and I heard him screaming 'This is fun... this is fun!' and listened more closely because I couldn't believe... I doubted, how can anyone be screaming this? and I heard, "This is such fun! This is such fun!"

Chan is among dozens of witnesses and law enforcement to take the stand in the trial that began with opening statements on Sept. 5. The trial is expected to last about three weeks.

Alissa pleaded not guilty by reason of insanity; he's now facing several charges including 10 counts of first-degree murder. Prosecutors aim to prove he was sane the day of the shooting. Jurors must determine if Alissa was sane at the time of the attack at the grocery store on South Table Mesa.