By Mary Slosson
(Reuters) - An "intentional" house explosion on Sunday near Tacoma, Washington killed the husband and two sons of a Utah woman missing since December 2009, fire department officials said.
The explosion happened shortly after a Child Protective Services worker dropped off the two children of Josh Powell for a supervised visit in Puyallup, Washington. Powell then prevented the worker from entering the house, according to Graham Fire and Rescue Deputy Chief Gary Franz.
The worker reported smelling gas before the explosion, and was trying to report the incident to her supervisor when it happened, Franz said.
"Everything is telling us that this was intentional," Franz said. "This would be murder, if that was the case, on the part of Mr. Powell."
The two children, Charles Joshua Powell, 7, and Branden Timothy Powell, 5, were at the center of a bitter custody battle between their father and the parents of their missing mother.
A judge denied custody to Josh Powell on Wednesday due to the discovery of "extreme child porn" found by police in the Powell family residence, according to Pierce County Sheriff's Detective Ed Troyer.
That porn was believed to belong to his father, Stephen Powell. Custody was given to Susan's parents, Charles and Judy Cox, until Josh Powell agreed to undergo a psycho-sexual evaluation.
"I have always been a loving and devoted father," Josh Powell said in court documents in December of 2011. "My sons and I have a very close relationship and I am working diligently to get them back in spite of the lies people are saying about me."
Powell's wife Susan went missing in December 2009 and was last seen by her husband, according to court documents.
Powell told police that he took his two sons, aged 2 and 4 at the time, to go camping in subfreezing temperatures just after midnight on December 7, leaving his wife at home, according to court documents.
She was gone when he returned that afternoon, he told police, according to court documents. They also say that police searched the area where Powell said he took his children camping, but found no sign of a campsite.
A website dedicated to Susan Powell set up by her parents, friends and other family calls the circumstances surrounding their daughter's disappearance "suspicious."
Firefighters were still working to contain the blaze and remove the bodies from the smouldering house, Franz added.
"This is an ugly situation right here," he said.
Lawyers for Josh Powell and Susan Powell's parents did not respond to requests for comment.
(Reporting By Mary Slosson; Editing by Greg McCune)