A tragic house fire in Donnelly took the lives of four Friday night.

The coroner has identified the victims. Two were members of the Idaho National Guard. Lt. Col. James Harper III, 49; his 14-year-old son, James “JJ” Harper; MSgt. Erin Smith, 34; and her daughter Autumn Smith, who is either six or seven years old were killed. The sole survivor, William Smith, also a member of the Idaho National Guard and Erin’s husband, tried to save them.

A Fire Marshal on the case said he has narrowed the focus of the investigation to a propane-fueled fireplace on the main floor of the house. They can’t officially rule the cause until the investigation has been complete, which could still take a few weeks.

Witnesses said they heard a loud boom which would indicate an explosion.

JJ’s mother and stepfather said they will hold a memorial hike to Table Rock to honor him. The hike is set for Saturday, July 15 at 1 p.m.  A GoFundMe page has also been set up as a memorial fund for JJ.