NEW : Powell kids had gunshot wounds , autopsy shows . David Powell and his sons died of carbon monoxide poisoning . ` It really hurts my heart . Powell sent goodbye e - mails to his pastor , others just days before the fire . A Utah police chief vows to keep on the trail of Susan Cox - Powell 's killer .
NEW : Powell kids had gunshot wounds , autopsy shows . David Powell and his sons died of carbon monoxide poisoning . Powell sent goodbye e - mails to his pastor , others just days before the fire . A Utah police chief vows to keep on the trail of Susan Cox - Powell 's killer .