Video posted online appeared to show people on the floor inside the King Soopers store and two more outside on the ground, but the extent of their injuries wasn’t clear.
Boulder Police Chief Maris Herold announced at a press conference at 8:15 p.m. that Police Officer Eric Talley was among the fatalities. Talley, 51, was among the first responders on the scene. Herold called the officer’s actions “heroic.”
The names of other victims will not be released until their families have been notified. Herold said that she acknowledges there are families awaiting news of their loved ones.
“I am sensitive to that, and we will work around the clock to get this accomplished,” she said.
Boulder District Attorney Michael Doherty expressed condolences to all the victims, including Talley. “His life was cut much too short,” Doherty said, promising a “painstaking investigation.”
Boulder police commander Kerry Yamaguchi told a press conference earlier in the evening that one person of interest was taken into custody and was being treated at a hospital for his injuries.
Video footage showed officers escorting a shirtless man with blood running down his leg out of the store in handcuffs, before he was put on a stretcher and loaded into an ambulance.
Doherty said that the man is the alleged shooter.
The incident drew a massive response from law enforcement, including multiple police vehicles, SWAT teams, and at least three helicopters were on the roof. The situation remained active more than two hours after the first reports of the incident, according to multiple reports.
Yamaguchi said the police department received a call about the incident just before 3 p.m.
He thanked the police response, including from Boulder law enforcement, the FBI, the ATF (Bureau of Alcohol, Tobacco, Firearms and Explosives), and other Denver metro agencies.
“Without that quick response we don’t know if there would have been more loss of life,” he said.
He noted that authorities were processing the crime scene.
An incident at an apartment building three miles away turned out to be unrelated to the supermarket shooting, Yamaguchi added.
Doherty said there will be a coordinated response between local, state, and federal law enforcement. “This is a tragedy and a nightmare for Boulder county,” he said, later adding, “we’ll stand united in support of the victims and their families to ensure that justice is done.”
Kelli McGannon, spokesperson for King Soopers, said the chain will defer all questions to law enforcement for the integrity of the investigation.
“Our hearts are broken over this senseless act of violence. The entire King Soopers family offers our thoughts, prayers, and support to our associates, our customers, and first responders who so bravely responded to these acts of violence,” she said at a press conference.
White House press secretary Jen Psaki wrote on Twitter that President Joe Biden was briefed on the shooting and “will be kept up to date by his team as there are additional developments.”
Colorado Gov. Jared Polis announced on Twitter, “My heart is breaking as we watch this unspeakable event unfold in our Boulder community. … I’m incredibly grateful to the brave men and women who have responded to the scene to help the victims of this senseless tragedy.”
At the time, he asked for patience from the public to allow local law enforcement to secure the site.
The Associated Press contributed to this report.