A sheriff's deputy was killed and four officers were injured Sunday in suburban Denver when a gunman fired more than 100 rounds in an ambush-style attack. 

The gunman was killed by additional officers who rushed to the scene. Police had been responding to a disturbance call at an apartment complex.

Douglas County Sheriff Tony Spurlock described it as an "ambush-style" attack on the officers.

They were "shot very, very quickly," he said. "They went down within seconds of each other."

“He knew we were coming, and we obviously let him know that we were there,” Spurlock said.

The gunman continued to fire as additional officers arrived at the complex.

Spurlock identified Deputy Zackari Parrish, 29, as the officer killed in the attack. He was married with two young children. He had been hit multiple times.

Parrish had been at the department about seven months and loved his job, Spurlock said.

The gunman was armed with a rifle, but Spurlock released no further details on the weapon. The incident is still under investigation; officials will view body camera footage and other evidence in coming days.