A man suspected of killing three people at a Colorado Walmart on Wednesday evening (local time) has been arrested.
The gunman entered the Thornton store and fired a handgun at a group of people, before fleeing in a car. Two men died at the scene, and a woman died later in hospital.
Scott Ostrem, 47, was handcuffed and bundled into a police car on Thursday morning, 14 hours after the incident. Police had issued a warrant for his arrest the night before, and received an anonymous tip for his whereabouts.
Thornton Police Department spokesman Victor Avila told Reuters that Ostrem was a "local" but said he could not give details while the investigation was under way.
One witness told 9 News he heard multiple gunshots while at the self-service checkout, and immediately started running. Another said her son heard about 30 shots and helped rescue an elderly woman.
In an interview with Fox News Denver, a Walmart employee said everyone in the store got down and started screaming when gunfire started.
Police are speaking to 48 witnesses and reviewing security footage.
The scene of the attack is within 30 kilometres of both the Columbine High School massacre of 1999 and the movie theatre shooting in Aurora in 2012.