When a lone shooter opened fire in a Colorado Walmart Nov. 1, so many shoppers drew their own handguns in defense that it actually delayed police identification of the culprit.
Scott Allen Ostrem, 47, entered the Walmart in Thorton, Colorado, and fatally shot two men and one woman, according to The Denver Post. The shooting prompted many to run for cover. But, some drew out their own concealed weapons in defense.
After the shooting, Ostrem walked out of the store and drove off, prompting an all-night manhunt. Police say their investigation was delayed as surveillance footage showed too many people carrying handguns, and officials had to spend time eliminating each one as a suspect.
"Once the building was safe enough to get into it, we started reviewing [the surveillance video] as quickly as we could," said Thornton Police spokesman Victor Avila.
Surveillance video showed that multiple individuals had pulled weapons.
"At that point, as soon as you see that, that’s the one you try to trace through the store, only to maybe find out that’s not him, and we’re back to ground zero again, starting to look again," Avila added. "That’s what led to the extended time."
Avila did not comment on whether any other individuals who pulled a weapon at the time of the shooting were brought in for questioning. He also said he could not quantify how much time investigators would have saved if others hadn't pulled out their guns.
"It was a very, very fluid situation, and we had to go with what was being presented at the time," he said.
Ostrem was arrested the next morning when he was spotting driving past his Denver apartment only seven miles south of the store, according to The New York Times.
Inside Ostem's apartment, officials found a suitcase filled with camouflage pants, a cardboard rifle box, and journal pages with references to Norse and Celtic myths.
"Give up trying to do anything nothing works works," one page read.
A Walmart customer present at the shooting told The Denver Post that she was upset none of the armed civilians actually tried to stop Ostem.
"Why wouldn’t they draw their guns and shoot him?" she said.
But Joseph Pollini, deputy chair of the Law and Police Science Department at New York's John Jay College of Criminal Justice, said that it's better to let the authorities do their job. While armed citizens can sometimes help apprehend a suspect, he says that usually it creates more of a problem for police.
“It can work both ways,” he said. "In one, you have law abiding citizens present at the scene of a shooting that could terminate it, assist in apprehending the individual. But generally as a rule, you turn to the police for that aspect.
"It’s not common for civilians to do the job of police, and the fact that they carry firearms can very much complicate things.”