Two men and a woman were killed Wednesday night during a shooting at a Walmart Supercenter in the Denver suburb of Thornton, police said.
"The shooting happened inside the store," Thornton Police Officer Victor Avila told CNN.
Authorities are looking for a man they said entered the store and randomly fired a handgun near the cash register, striking three people
"We believe as of right now that the shooting was random," Avila said.
Video from CNN affiliates showed a Walmart Supercenter parking lot filled with emergency vehicles.
Jennifer Biglands said her sister called her frantically from the store and said she heard seven or eight shots.
Thornton is just north of Denver.