Authorities are trying to determine why a sniper ignited a blaze then ambushed and fatally shot and killed two responding firefighters.

Authorities say two firefighters were killed and another was badly injured after they were ambushed and shot while responding to a wildfire near Coeur d’Alene, Idaho on Sunday afternoon.

Idaho firefighters ambushed by sniper while responding to brush fire near Canfield Mountain, leaving two dead and one injured as authorities urge residents to avoid the area.