BRIGHTON — A judge entered a not guilty plea Friday for the man accused of killing three people at a Thornton Walmart in 2017. The trial is scheduled to start in January.

Adams County District Judge Mark Warner took that action over objections from an attorney for Scott Ostrem, who requested more time to consider a plea of not guilty by reason of insanity.

Warner told defense attorney Emily Fleischmann that court rules would allow her to change the plea later if there is “good cause.”

Ostrem, 48, faces 52 separate felony charges – including six separate counts of first-degree murder – in the burst of gunfire that left three people dead last Nov. 1 and sent hundreds of others running for their lives.

At Friday’s hearing, Ostrem sat silently in a yellow-and-white jail jumpsuit.

Nearly two dozen people packed one side of the courtroom, all family members and friends of the three people who died in the incident – Pamela Marquez, 52, Carlos Moreno, 66, and Victor Vasquez, 26.

There was a brief outburst when one woman stood up, said, “f——— coward ... f——- liar and coward,” and left. Another man muttered, “He’s a human waste” before leaving.

At that point Judge Warner admonished those in the courtroom to refrain from saying anything.

Ostrem’s trial is expected to start Jan. 28, 2019, and last 10 days.

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One unanswered question: Whether Adams County District Attorney Dave Young will seek the death penalty in the case – a decision he has to make within 63 days.

“That’s a process,” Young said. “And the process involves meeting with defense counsel, learning whatever mitigation they may have in the case, certainly meeting with all the victims in this case. And then meeting with my trial team and doing what we think is a just decision for this case."

At a preliminary hearing June 29, a detective’s testimony offered a chilling, detailed look at the attack that began just after 6 p.m. last Nov. 1 in the store at 9901 Grant St. and last roughly 21 seconds.

Surveillance footage showed a man alleged to be Ostrem parking a car in front of the store, its headlights flickering as he apparently locked it.

From there, the man walked into one of the store's main entrances, stopping near the cash registers and opening fire, Thornton police detective Douglas Parker testified at that hearing.

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The first round tore across the store at precisely 6:09 p.m., ricocheting into a dressing room.

The second shot, fired two seconds later, hit Moreno in the shoulder and head, killing him, Parker testified. He'd been shopping with his wife and daughter.

The gunman turned, firing a third shot. The bullet hit Marquez, according to Parker, who moments before had been at the registers with her husband and was now running for her life. She died a short time later at a hospital.

Eight seconds after first squeezing the trigger, the gunman fired the fourth shot, killing Vasquez, who had been at the store with his mother and his fiancée, Parker testified.

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On his way toward an exit, the detective testified, the gunman fired three more rounds -- piercing packages of beef jerky, shattering a cash register, blasting through a wall – and walked out.

He described the gunman walking through a “sea” of running customers.

Parker described how detectives, using video images of the gunman’s car, were able to locate its registration and identify Ostrem as the suspect.

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Ostrem faces six counts of first-degree murder – two for each of the three people who died. One count in each case alleges that Ostrem committed the killings after deliberation, the other that he committed the crimes with extreme indifference.

He also faces 45 counts of attempted first-degree murder and a single charge of committing a violent crime, a sentencing enhancer.

Contact 9NEWS reporter Kevin Vaughan with tips about this or any story: kevin.vaughan@9news.com or 303-871-1862.