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

Law enforcement is piecing together evidence of what happened in Idaho after officials say a man started a brush fire then ambushed first responders and killed two firefighters. The suspect was found dead after police were able to ping a cellphone to pinpoint his location.

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.