PIERCE COUNTY, WA (CNN/ KING / KIRO / KSTU) – The case of a missing Utah woman took a tragic turn Sunday when Washington State authorities say they believe Josh Powell deliberately set off an explosion that took his life and the lives of his two boys. Josh Powell was the focus of an investigation into the disappearance of his wife, Susan Cox-Powell. Deputies said it appears Powell sent an email that apologized and said goodbye shortly before the fire. "This is all on him. He set this up. He did it. He is the one who started the fire," said Ed Troyer, the Pierce County Sheriff's office spokesman.