Officials reported that first responders came under "active sniper fire" at the Canfield Mountain Trailhead.
After an exchange of gunfire with law enforcement, the suspected gunman was found dead with a firearm near the scene, with authorities believing he acted alone.
The Kootenai County Sheriff stated the firefighters were ambushed and "did not have a chance," with police investigating if the fire was intentionally set to lure them.
Fire crews continue to battle the Nettleton Gulch Fire, which has scorched approximately 20 acres, after security threats were cleared and shelter-in-place orders lifted.