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.

Multiple firefighters in Idaho were attacked while they were responding to a fire in Idaho on Sunday, Gov. Brad Little said.