A gunman killed at least six people, including a police officer, at a supermarket in Boulder, Colorado, on Monday, law-enforcement officials briefed on the investigation told The Wall Street Journal.

A live television feed showed a handcuffed and bloody man being led away from the scene.

The shooter’s motive hasn’t been determined, one of the law-enforcement officials said.

Witnesses described to local television stations how a man suddenly opened fire in the King Soopers store, sending shoppers into a panic and trying to escape as police rushed to the scene.

Boulder police ordered residents to shelter in place at a nearby location while they responded to a report of an “armed, dangerous individual.”

Aerial footage also showed a massive law enforcement presence outside the supermarket. The supermarket where the incident took place is located about two miles from the University of Colorado’s flagship campus, according to Reuters.

Colorado Governor Jared Polis commented on the incident and said, "Like my fellow Coloradans, I am closely watching unfolding events at King Soopers in Boulder. My prayers are with our fellow Coloradans in this time of sadness and grief as we learn more about the extent of the tragedy."