An Alaska State Trooper investigating a dangerous driver on the Kenai Spur Highway shot an aggressive dog in the head Monday night in Nikiski, according to officials.

A Wednesday AST dispatch says troopers received a Kenai Police Department message just before 10 p.m. Monday about a dangerous driver in a vehicle headed north on the highway. The driver was also listed as having a federal arrest warrant for firearms offenses.

Troopers found the vehicle at a Nikiski residence, and were approaching to contact the home's occupants when an unknown person released an aggressive dog. AST spokesperson Beth Ipsen says the medium-sized dog immediately charged two troopers, the first of whom pepper-sprayed the animal -- at which point it changed course for the second trooper.

“A trooper fired his duty pistol at the dog at near contact range, striking the dog in the head,” troopers wrote in the dispatch. “The trooper sustained minor injuries from a fall while trying to avoid the dog.”

The dog then fled, but reportedly survived the gunshot wound and was taken to a veterinarian for treatment by people associated with its owner.

Ipsen says the incident remains under investigation and no charges have yet been filed.