Emergency crews and police work at the scene in response to a shooting at Walmart in Thornton, Colo., Wednesday, Nov. 1, 2017. Police in suburban Denver say they are responding to a shooting at a Walmart with "multiple parties down." Dozens of police cars and emergency vehicles converged at the store. (John Leyba/The Denver Post via AP)
The Associated Press
THORNTON, Colo. (AP) - Two men and a woman were killed in a shooting inside a suburban Denver Walmart on Wednesday night that forced customers to either hide or flee.
Thornton police reported "multiple parties down" and advised people to stay away from the area as dozens of police cruisers and emergency vehicles raced to the scene.
The men died at the store, and the woman died at a hospital.
Police spokesman Victor Avila said a man nonchalantly entered the store and fired a handgun into a group of people before fleeing in a car. No one has been arrested.
"This is a very heinous act," Avila said. "We don't know exactly what the motive of the person was, but it was certainly a terrible act."
The spokesman said there is currently no indication that the shooting was an act of terror.
Aaron Stephens, 44, was in the self-checkout line when he heard a single shot followed by two more bursts of gunfire before people started running for the exits.
"The employees started screaming. Customers were screaming. They were running like crazy, and I ran out too because I didn't want to get killed," he said.
Guadalupe Perez was inside the store with her young son when she heard what she thought was a balloon popping. A Walmart employee told her someone was shooting, and then Perez saw people running away yelling, "Let's go. Let's go. Leave the groceries."
"You see all these things in the news and you go through it, it's scary," she said. "But thank God we're OK and nothing happened to us."
Investigators, who have not released any other details about the circumstances of the shooting, were reviewing security footage and interviewing witnesses.
Meanwhile, special agents with the Bureau of Alcohol, Tobacco, Firearms and Explosives were helping police in the investigation.
The Walmart about 10 miles (16 kilometers) north of Denver is in a busy shopping center that includes restaurants, a movie theater and several other stores.
Ragan Dickens, a Walmart spokesman, said the company is working with investigators. He declined further comment.
Police investigate a shooting at a Walmart store in Thornton, Colo., Wednesday, Nov. 1, 2017. Thornton police tweeted Wednesday night that they were responding to a shooting with "multiple parties down." They advised people to stay away from the area as dozens of police cruisers and emergency vehicles raced to the scene. (Andy Cross/The Denver Post via AP)
The Associated Press
Walmart customers and employees are held back while emergency crews and police work on the grounds of Walmart during a shooting in Thornton, Colo., Wednesday, Nov. 1, 2017. Police in suburban Denver say they are responding to a shooting at a Walmart with "multiple parties down." Dozens of police cars and emergency vehicles converged at the store. (John Leyba/The Denver Post via AP)
The Associated Press
Employees exit the parking lot after a gunman opened fire inside of Walmart in Thornton, Colo., Tuesday, Nov. 1, 2017. Thornton police tweeted Wednesday night that they were responding to a shooting with "multiple parties down." They advised people to stay away from the area as dozens of police cruisers and emergency vehicles raced to the scene. (AAron Ontiveroz/The Denver Post via AP)
The Associated Press
Darlene Jackson sits on an overturned shopping cart as she and fellow shoppers and employees gather outside after a gunman opened fire in Walmart in Thornton, Colo., Tuesday, Nov. 1, 2017. Police in Thornton announced the shooting in a tweet Wednesday evening and advised people to stay away from the area. Dozens of police cars and emergency vehicles converged at the store. (AAron Ontiveroz/The Denver Post via AP)
The Associated Press
Walmart employees gather together outside away from the scene of the Walmart store where a shooting occurred inside the store, Wednesday, Nov. 1, 2017, in Thornton, Colo. Thornton police tweeted Wednesday night that they were responding to a shooting with "multiple parties down." They advised people to stay away from the area as dozens of police cruisers and emergency vehicles raced to the scene. (Helen H. Richardson/The Denver Post via AP)
The Associated Press
Police guard the front entrance to Walmart where a shooting occurred inside the store, Wednesday, Nov. 1, 2017, in Thornton, Colo. Thornton police tweeted Wednesday night that they were responding to a shooting with "multiple parties down." They advised people to stay away from the area as dozens of police cruisers and emergency vehicles raced to the scene. (Helen H. Richardson/The Denver Post via AP)
The Associated Press
People watch police activity at the scene of a shooting inside Walmart, Wednesday, Nov. 1, 2017, in Thornton, Colo. Thornton police tweeted Wednesday night that they were responding to a shooting with "multiple parties down." They advised people to stay away from the area as dozens of police cruisers and emergency vehicles raced to the scene. (Helen H. Richardson/The Denver Post via AP)
The Associated Press
A father and his scared daughter, who were customers inside Walmart, are escorted out of the parking lot and away from the scene of the Walmart store where a shooting occurred inside the store, Wednesday, Nov. 1, 2017, in Thornton, Colo. Thornton police tweeted Wednesday night that they were responding to a shooting with "multiple parties down." They advised people to stay away from the area as dozens of police cruisers and emergency vehicles raced to the scene. (Helen H. Richardson/The Denver Post via AP)
The Associated Press
People stand across the street from a shooting investigation at a Walmart store, Wednesday, Nov. 1, 2017, in Thornton, Colo. Several people were killed in a shooting inside a suburban Denver Walmart on Wednesday night, forcing customers to either hide in the store or frantically run for the doors. Thornton police advised people to stay away from the area as dozens of police cruisers and emergency vehicles raced to the scene. (Andy Cross/The Denver Post via AP)
The Associated Press
Several people were killed in a shooting inside a Walmart, forcing customers to either hide in the store or frantically run for the doors, Wednesday, Nov. 1, 2017, in Thornton, Colo. Thornton police advised people to stay away from the area as dozens of police cruisers and emergency vehicles raced to the scene. (AP Photo/P. Solomon Banda)
The Associated Press
Several people were killed in a shooting inside a Walmart, forcing customers to either hide in the store or frantically run for the doors, Wednesday, Nov. 1, 2017, in Thornton, Colo. Thornton police advised people to stay away from the area as dozens of police cruisers and emergency vehicles raced to the scene. (AP Photo/P. Solomon Banda)
The Associated Press
Several people were killed in a shooting inside a Walmart, forcing customers to either hide in the store or frantically run for the doors, Wednesday, Nov. 1, 2017, in Thornton, Colo. Thornton police advised people to stay away from the area as dozens of police cruisers and emergency vehicles raced to the scene. (AP Photo/P. Solomon Banda)
The Associated Press
Walmart employees and customers that were inside the store wait to hear what to do from police as they stand behind police tape outside of a Walmart store where several people were killed in a shooting, Wednesday, Nov. 1, 2017, in Thornton, Colo. Investigators, who have not released any details about the circumstances of the shooting, were reviewing security footage and interviewing witnesses to get a description of the shooter. (Helen H. Richardson/The Denver Post via AP)
The Associated Press