Law enforcement authorities in Marion County, Ore., are seeking whoever is responsible for fatally shooting a 23-year-old Arabian mare while she grazed in her pasture near Silverton earlier this week.

Marion County Sheriff’s Department Public Information Officer Don Thomson said department personnel discovered the animal on May 2 after area residents reported hearing a single rifle shot.

Marion County Deputy Chris Helbling said the mare had sustained a single rifle shot wound to her left shoulder. The horse died at the scene, he said.

Investigators believe the shooting was deliberate, Thomson said