The suspected shooter, a 17-year-old, is in custody while another suspect is still at large.
DPS detectives were in the area of 37th Avenue and Portland Street working on an operation to make an arrest when a car drove up to them and a person pointed an assault rifle at them and shot at the troopers, investigators said.
The troopers returned fire. The troopers were not injured.
A DPS spokesperson said the troopers were in an unmarked vehicle but were wearing clothing that identified them as law enforcement.