BOULDER: A shooting at a Colorado supermarket killed multiple people Monday, including a police officer, and a suspect was in custody, authorities said.

Boulder police Cmdr. Kerry Yamaguchi said at a news conference that the suspect was getting medical treatment and there was no further threat to the public but didn’t give more details on the shooting or how many people were killed. Officers had escorted a shirtless man with blood running down his leg out of the store in handcuffs but authorities would not say if he was the suspect.

Investigators know how many people died, but their families were still being notified so the number of victims wasn’t being released yet, Boulder County District Attorney Michael Dougherty said.

“This is a tragedy and a nightmare for Boulder County, and in response, we have cooperation and assistance from local, state and federal authorities,” Dougherty said.

Yamaguchi said police were still investigating and didn’t have details on a motive for the shooting at the King Soopers store in Boulder, which is about 25 miles (40 kilometers) northwest of Denver and home to the University of Colorado.

Dean Schiller told The Associated Press that he had just left the supermarket when he heard gunshots and saw three people lying face down, two in the parking lot and one near the doorway. He said he “couldn’t tell if they were breathing.”

Law enforcement vehicles and officers massed outside the store, including SWAT teams, and at least three helicopters landed on the roof. Some windows at the front of the store were broken.

At one point, authorities said over a loudspeaker that the building was surrounded and that “you need to surrender.”

Sarah Moonshadow told the Denver Post that two shots rang out just after she and her son, Nicolas Edwards, finished buying strawberries. She said she told her son to get down and then “we just ran.”

Once they got outside, she said they saw a body in the parking lot. Edwards said police were speeding into the lot and pulled up next to the body.

“I knew we couldn’t do anything for the guy,” he said. “We had to go.”

James Bentz told the Post that he was in the meat section when he heard what he thought was a misfire, then a series of pops.

“I was then at the front of a stampede,” he said.

Bentz said he jumped off a loading dock out back to escape and that younger people were helping older people off of it.

One person was taken from the shooting scene to Foothills Hospital in Boulder, said Rich Sheehan, spokesman for Boulder Community Health, which operates the hospital.

Colorado Gov. Jared Polis tweeted a statement that his “heart is breaking as we watch this unspeakable event unfold in our Boulder community.”

Police had told people to shelter in place amid a report of an “armed, dangerous individual” about 3 miles (5 kilometers) away from the grocery store but said at the news conference later that it wasn’t related to the shooting.

The FBI said it’s helping in the investigation at the request of police.

White House press secretary Jen Psaki tweeted that President Joe Biden had been briefed on the shooting.

In a statement, the King Soopers chain offered “thoughts, prayers and support to our associates, customers, and the first responders who so bravely responded to this tragic situation. We will continue to cooperate with local law enforcement and our store will remain closed during the police investigation.”

Kevin Daly, owner of Under the Sun Eatery and Pizzeria Restaurant a block or so from the supermarket, said he was in his shop when he saw police cars arriving and shoppers running from the grocery store. He said he took in several people to keep them warm, and others boarded a bus provided by Boulder police and were taken away.