Thornton Police say they don't have a motive for a Nov. 1 shooting at a Walmart Supercenter that left three people dead, but they do have the suspected shooter in custody.
Police arrested Scott Ostrem, 47, just after 8 a.m. Nov. 2 while he was stopped at a traffic light near 72nd Avenue and Federal Boulevard in Westminster.
"The officers were right on his tail as they saw him coming by," police department spokesperson Victor Avila said. "Fortunately, we had a traffic light that was there, and traffic was backed up because obviously, we were in the middle of traffic-time. So he did not have the opportunity to be able to leave if that was what he chose."
Avila said police used a flash-bang grenade to distract Ostrem and he was taken down without incident.
Avila said Ostrem allegedly walked into the southern end of the Walmart at 9900 Grant St. at about 6:10 p.m. Nov. 1, opened fire, turned and walked right out.
"He came in from the front of the store, displayed the weapon and just started shooting," Avila said.
Police responded within minutes to find three people down. Two men were declared dead at the scene while the third person, a woman, later died at an area hospital.
The Adams County Coroner identified the victims as 66-year-old Carlos Moreno, of Thornton, 26-year-old Victor Vasquez of Denver and Pamela Marques, 52, of Denver. Avila would not comment on if there was a connection between the three victims or with Ostrem.
The family of Victor Vasquez has set up a Go Fund Me fundraiser for his family, a fiancee and two daughters. According to the website, Vasquez and his fiancee, Alexis, are expecting a third child. His Facebook page describes him as self-employed.
According to her Facebook page, Marques grew up in the Denver-area and attended Adams City High School. Facebook lists her employer as Tharco, a Denver maker of packing goods.
Moreno was from Clovis, New Mexico, according to Facebook.
As of Thursday morning, Avila said police do not know of a motive or if the suspect acted alone.
"No motive has been established, but we did just get our suspect," said Matt Barnes, department spokesman. "So, we are hoping that something further will come out soon."
Avila said hundreds of people were running everywhere when police arrived at the scene of the shooting.
"When (you) are talking about people running in all directions, you don't know who is good and who is bad," Avila said. "It would be very easy for someone to bed down and become a victim while they were truly an assailant. So we had to search the whole area, and that included the parking lot."
Detectives located a Walmart employee and began reviewing surveillance footage right away, but that work was complicated by the number of people in the store at the time.
"It was mass chaos in there," Avila said. "If the surveillance ever becomes available, you'll see that there were people running everywhere. That's truly what took the longest amount of time - being able to decipher exactly what we had."
Avila said there were armed citizens on the scene as well, which further slowed their work.
"In the surveillance, we saw people holding something that appeared to be a gun," Avila said. "So, we had to follow that person all through the store."
Police had to watch the tapes and track those people to make sure they were not involved in the shooting.
Using the surveillance footage, police were able to identify Ostrem at about 10:30 p.m. and his car, a red 2017 Mitsubishi Mirage, as well as his address. They published his name, photo and description via social media at about 11 p.m. and obtained a search warrant for his 7121 Samuel Drive address. Police searched Ostrem's residence, but he was not there.
"We put his face up on social media, and tips started coming in," Avila said. "People said they thought they knew this guy and that he was frequently in that area."
Officers were on the lookout and saw Ostrem stopped in traffic, arresting him in the middle of the road.
"He was positively identified by officers and by self-admission," Avila said. "He did admit to being Scott Ostrem."
Mayor Heidi Williams said she was on the scene until about midnight Wednesday. She applauded officers and Walmart employees for keeping control of the scene.
"I know it was frustrating because it took a long time, but the officers did their job," she said. "There were steps to follow and they didn't want to jump the gun. They wanted to catch him, and they did. So, overall, the best thing we can do is to stay out of the way."
The Walmart store was closed on Nov. 2, according to a member of the management team who declined to identify himself, but employees were gathering in the front of the store at about 9:30 a.m. for a staff meeting.
At 1 p.m. Nov. 2, police announced that they were releasing personal items that store patrons had left behind in the chaos. Patrons were urged to come to the store to collect their belongings.