Cops arrested 47-year-old Scott Ostrem on Thursday morning.
Three people are dead following a shooting rampage at a Colorado Walmart that led to an overnight manhunt before an arrest came Thursday morning.
Thornton Police said shots rang out Wednesday night and originally reported "multiple people down" before it emerged that two men and one woman were shot and killed.
A lone suspect was identified by police Thursday as 47-year-old Scott Ostrem.
Witnesses said the gunman walked into the store "nonchalantly" and opened fire randomly on a group of people, according to Thornton Police Department.
Customers at the bustling big-box store were forced to take cover and hide, while others fled for the doors, as police were called around 6 p.m.
The two men died at the scene. The female victim was rushed to a hospital where she later succumbed to her injuries.
The three victims were the only people shot.
Victor Avila, the public information officer of the Thornton Police Department, addressed the media outside the store late Wednesday.
"Witnesses indicated that there was an adult male that entered that southern doorway and just randomly began shooting at people," Avila said. "Witnesses then say that they observed that the suspect then fled the area in a red Mitsubishi Mirage, four-door, hatchback."
Ostrem was taken into custody around 8 a.m. and no motive was immediately released.
