A suspect of the fatal shooting that killed three people inside a Walmart supermarket in the U.S. state of Colorado was arrested Thursday morning, local police confirmed.
"Walmart homicide suspect Scott Ostrem has been taken into custody," Thornton Police Department said on its official tweet page, 14 hours after the heinous act occurred around 6:00 p.m. Wednesday evening (0030 GMT, Thursday) in Thornton, a Denver suburb, and left three dead.
The suspect was identified as 47-year-old Scott Ostrem, who was described by witnesses as a cold blood murder. Police said he walked into the south entrance of the store and began shooting with a handgun randomly, then fled the scene in a red Mitsubishi car.
At a press conference Thursday noon, Thornton police spokesman Victor Avila disclosed more details about the arrest, saying that a citizen tip helped police to locate the suspect's residence.
Policemen and other federal law enforcement personnel surveilled the area all night and found the Mitsubishi Mirage with Colorado license plate in the morning, Avila said, adding that morning traffic ahead the suspect stopped him from escaping, allowing officers to arrest him in car, about one block away from his apartment.
Avila told reporters earlier that Ostrem said nothing when he opened fire at the supermarket. So far, policemen had no idea about his motive but there are no indications it is terror-related.
"From what we have right now it appears to be random. It's a crazy world we live in." Avila said.
"He walked in very nonchalantly with his hands in the pockets, raised a weapon and began shooting. Then he turns around and walks out of the store."
Avila confirmed that Ostrem had minor criminal history.
The Denver Post reported that court records show Ostrem was arrested in 2013 for driving while impaired and filed for bankruptcy two years later.
Avila also explained why it cost policemen 5 hours after the shooting to find out that the suspect was still at large, saying officers must keep safety of other people at the scene first, and then check the monitors' footage and use database to identify who is the shooter.
The Denver Post cited Avila's words as saying that when the gunman opened fire, most of shoppers inside the supermarket screamed and ran for cover, but others pulled out their own handguns.
There was no exchanging fires between the gunman and shoppers, but those who drew weapons delayed the investigation since authority had to identify the real assailant and make sure there was no more shooter.
The shooting incident triggered a new wave of advocate for gun control on social media.
A user named NyxSea tweeted "this is how mass shootings have become normal in the US. When I read that there was 1 death #ThorntonWalmartShooting I said thank God."
"Thank God it was only 1 death, There should be no death #ThorntonWalmartShooting. What to do about guns?" he retweeted three minutes later.
"Thanks to @NRA lobbyists and lawmakers beholden to them, THIS is what America looks like. THIS is every city, every day," tweeted Shanon Watts, founder of Moms Demand Action for Gun Sense in America, a grassroots organization working to end gun violence.
"Why does this keep happening. And even in my home state. Why is Colorado known for shooting?" another user named Karlie tweeted.
The state of Colorado witnessed a mass shooting in July 2012. Twelve people were killed and 59 others injured in Aurora, a suburb 10 miles (16 km) east of Denver, where a heavily armed gunman burst into a packed theater and sprayed the audience with bullets.
According to the non-profit organization Gun Violence Archive, there have been 299 mass shooting incidents so far this year in the United States. Also on Wednesday, a man shot dead his ex-girlfriend before turning the gun at himself in a murder-suicide attempt in the Manhattan borough of New York City.
An estimated 30,000 Americans die each year from guns, and the country is split on whether to have controls on guns or follow the 1789 Second Amendment of the U.S. Constitution which protects the right of the people to keep and bear arms.