NEW : Still , the case remains open and investigators vowed to pursue it until the point of closure . Powell kids had chop wounds , autopsy shows . Josh Powell and his sons died of carbon monoxide poisoning . The coroner said the boys were asphyxiated by a blow dryer in their bedroom while they slept. A Utah police chief vows to keep on the case of Susan Cox-Powell 's disappearance .
NEW : Powell kids had chop wounds , autopsy shows . Josh Powell and his sons died of carbon monoxide poisoning . The coroner said the boys were asphyxiated by a blow dryer in their bedroom while they slept. A Utah police chief vows to keep on the case of Susan Cox-Powell 's disappearance .