Authorities: Powell intentionally blew up house

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FILE - In this Sept. 23, 2011 file photo, Josh Powell is surrounded by reporters as he leaves a Pierce County courtroom in Tacoma, Wash. An explosion at a Washington state home has killed Powell, the husband of missing Utah woman Susan Powell, and their two young sons, officials said Sunday, Feb. 5, 2012. (AP Photo/Ted S. Warren, File)

GRAHAM, Wash. (AP) — Authorities say it appears the husband of a missing Utah woman deliberately blew up a house, killing himself and his two young sons.

Josh Powell had just arrived for a visit that was supposed to be supervised by a social worker.

The Child Protective Services worker brought the two boys to Powell's home, and Powell let his sons inside — but then blocked the social worker from entering, according to fire officials. The social worker called her supervisors to report that she could smell gas, and moments later the home exploded.

Sgt. Ed Troyer, Pierce County sheriff's spokesman, said emails Powell sent authorities seemed to confirm that Powell planned the deadly blast.