What began as a routine response to a brush fire on northern Idaho’s Canfield Mountain turned deadly Sunday after firefighters reported someone shooting at them while they battled the flames.

Wess Roley, 20, was found dead with a gun nearly six hours after the attack, and investigators say he acted alone, according to the Associated Press.

Two firefighters were shot dead and a third wounded on an Idaho mountain when they were ambushed by a man who set the fire to lure them to the area, the local sheriff says.