Boulder Police Department Commander Kerry Yamaguchi said "multiple people" were killed in a shooting at King Soopers, including one Boulder police officer.
"We had a very tragic incident today here at the King Soopers," he said at a news conference on Monday. "During this trying time, I would ask the media and the public to honor the privacy of the officer's family and his coworkers here at the police department."
He said the quick response from law enforcement from around the area saved lives.
Yamaguchi said officers arrived "within minutes of the initial 911 calls and entered the building very quickly."
"Without that quick response, we don't know if there would have been more loss of life," he said.