Rikki Olds thought the noise she heard coming from outside was someone repairing the roof of the King Soopers. Seconds later, she tilted her head as a man in dark clothing and a tactical vest ran through the west doors and shot her once, killing her, the lead investigator testified Monday.

Jurors somberly watched defendant Ahmad Alissa’s actions on store surveillance video, which was shown on a courtroom monitor, along with maps and digital re-enactments, in the third day of Alissa’s murder trial in Boulder County.

The footage showed victim Denny Stong jump between cash register 14 and 15, and start crawling before the defendant allegedly shot him three times.

Olds was the fourth of 10 people who lost their lives that day. Stong was the fifth. The bodies of Neven Sanisik, Kevin Mahoney, and Tralona Bartkowiak were in the Table Mesa shopping center parking lot, shot just seconds before and the first three to die that day in March 2021.

In the courtroom at the defense table, Alissa watched the monitor attached to the wall on his right side as footage showed that quiet afternoon, when a neighborhood grocery store became the scene of a mass shooting.

When large photos of each victim filled the screen and their lives described, he removed his glasses and pinched the skin between his eyes. Some of the jurors looked at the defendant as the photos were shown.

Alissa, 25, faces 55 counts overall, including 10 counts of first-degree murder, 38 counts of attempted first-degree murder, one count of first-degree assault and six counts of possessing large-capacity magazines during the commission of a felony in connection to the mass shooting that occurred at the King Soopers on Table Mesa Drive on March 22, 2021.

Alissa has pleaded not guilty by reason of insanity, and his attorneys have acknowledged that he was the shooter who killed the people in the parking lot and in the store at 3600 Table Mesa Drive.

It is the first time that video surveillance has been shown in the courtroom.

Several family members who attended the trial in-person ducked their heads or sobbed as they watched their loved ones in the last moments of their lives.

Before lunch, public defender Kathryn Herold asked 20th Judicial Chief Judge Ingrid Bakke to instruct the gallery to keep their emotions and whispering in check, so as not to prejudice the jury.

Mark Suban, a Laboratory Shooting Reconstruction specialist, testified that he reviewed police body-worn camera video and store surveillance to put together a timeline. There was so much video, it took him eight months to compile it.

Suban color-coded his graphic map to correspond with the movements of the gunman, murder victims, and survivors.

Some places had no camera view, which created a “blank zone” but corresponding time codes and angles enabled him to follow the shooter, shoppers and store workers. The interactive digital video with orange, blue and purple dots made it easy for the jury to track the 68 seconds Alissa took to allegedly execute the mass shooting.

Former Boulder Police lead investigator Sarah Cantu was asked what the common factors were between the victims.

“Most of them were in his line of sight,” she said. “They were trying to get away. He pursued them and shot them until they stopped moving.”

Some time between 2:25 and 2:30 p.m., Boulder Police Ofc. Bryan Capobianco got an active shooter call, hopped in his vehicle and raced to the King Soopers.

“Your foot gets a little heavier when you get a call like that,” he testified.

Once at the store parking lot, Mahoney’s body was lying in the road; Bartkowiak’s body was nearby.

Capobianco entered the store with Boulder Police officers Eric Talley, whom he described as a mentor, and Pam Gignac. Once inside, he described what he called an “Oh, s*** moment.”

What met them was not a chaotic scene, but a quiet grocery stores with nowhere to duck for cover except for racks of knick-knacks.

“There was lounge elevator type of music and the distinct smell of gunpowder,” he said.

The silence didn’t last. Several “loud” gunshots rang out and Capobianco and Gignac retreated to the parking lot. He did not realize that Talley was down until he returned with a second wave of officers and saw his body.

“I knew it was Ofc. Talley because he was the only one of the three of us that would wear a standard uniform,” he said and added that Talley’s bullet-proof vest was on the inside of his clothing.

Gignac later testified that Talley fell after two shots.

“I knew (he was dead) when it happened. He was running, but when the shots rang out he just dropped,” she said.

When Dougherty asked how many children Talley had, Capobianco chocked at the number.

“Seven,” he answered.

Talley’s family, including several of his children, were in the courtroom Monday. One, a woman, left the room crying after Capobianco left the stand. He walked out with his father, who flew in from New York to support him.

Day 4 of the trial resumes at 9 a.m. Tuesday.