KUNA, Idaho (AP) — Authorities in southwest Idaho are trying to find out who is responsible for shooting 75 power line insulators.

The Ada County Sheriff's Office tells KTVB-TV (http://bit.ly/1wjSX7N) in a story on Tuesday that the insulators belonging to PacifiCorp were damaged in Late October about 5 miles south of Kuna.

Deputies say shotgun casings littered the ground near the power lines.

PacifiCorp is offering a reward of $5,000 for information leading to a conviction.