A man died Sunday after exchanging gunshots with a Fort Collins, Colo., police officer at an apartment complex after the officer responded to a suspicious person call, authorities said.

The officer was shot in his bulletproof vest. It's not known how many times the suspect was shot. Both men were taken to the Medical Center of the Rockies in Loveland. Fort Collins patrol officers are required to wear bulletproof vests.

A witness called police at 3:45 p.m. and reported seeing a suspicious person, Fort Collins Deputy Chief Cory Christensen told the Denver Post.

The police officer responded to the apartment complex and spotted a man lying on the floor in an apartment stairwell.

As the officer approached, the man pulled out a gun and shot the officer. The officer fired back, striking and mortally wounding the man, Christensen said.