THORNTON, Colo. — The man accused of opening fire inside a Thornton Walmart that left three people dead is due in court on Friday morning.

Scott Ostrem, 47, is facing three counts of first-degree murder for the shooting on Wednesday night.

He was identified as the gunman by security video recorded at the Walmart store at 9901 Grant St.

Police spent hours reviewing the images to come up with the ID. He was taken into custody after a 14-hour manhunt that lasted into Thursday morning.

A citizen tip led police to Ostrem’s residence at the Samuel Park Apartments at 7121 Samuel Drive. A SWAT team went inside on Thursday morning, but Ostrem was not found.

Just before 8 a.m., the 2017 red, four-door Mitsubishi Mirage associated with Ostrem drove past the apartment complex.

Law enforcement quickly took off and followed the vehicle, stopping it at West 72nd Avenue and Federal Boulevard where Ostrem was apprehended without incident.

He’s being held at the Adams County Detention Center and will make his first court appearance at 11 a.m. Friday.

Police have not said what the motive for the attack was.

Neighbors at the apartment building where he lived off West 72nd Avenue and Pecos Street said Ostrem was a loner.

They say he seemed angry and never socialized, and they would often see him coming and going while carrying what they say were weapons.

“He didn’t seem to have anybody,” neighbor Teresa Muniz said. “Being angry all the time. That’s what he seemed like, always angry. We didn’t even know his name ’til today.

“He’d be gone for a couple of hours, then come back with like a shotgun, a bow and arrow. He’d do karate, but he wouldn’t talk to anybody.”

“He’s pretty much been a loner,” neighbor Angela Lucero said. “Never thought he was capable of doing it. I saw him with rifle bags. I don’t know why he was so heavily armed.”

The Thornton Police Department said Ostrem walked into the south doors at the Walmart around 6:10 p.m. Wednesday and “nonchalantly” began firing with a handgun.

Victor Vasquez, 26 of Denver, and Carlos Moreno, 66 of Thornton, were pronounced dead at the scene. Pamela Marques, 52 of Denver, was taken to a hospital but later was pronounced dead.