GRAHAM, Wash. (AP) — Days after a judge ruled against him in a child custody hearing, a father of two young boys apparently blew up a house Sunday with all three inside — a tragic ending to a bizarre, long-running case that began when the man’s wife went mysteriously missing in Utah.

A Child Protective Services worker brought the two boys to Josh Powell’s home for what was to be a supervised visit, and Powell let his sons inside — but then blocked the social worker from entering, Graham Fire and Rescue Chief Gary Franz told The Associated Press.

The social worker called her supervisors to report that she could smell gas, and moments later the home exploded. What’s left of the house was still smoking Sunday afternoon, and fire crews were mopping up the scene.

Sgt. Ed Troyer, Pierce County sheriff’s spokesman, said emails Powell sent authorities seemed to confirm the Powell planned the deadly blast. Troyer didn’t elaborate on the contents of the emails.

Jeffrey Bassett, who represented Powell in the custody case, said he received a three-word email from his client just minutes before Powell and the two boys died. It said, “I’m sorry, goodbye.”

The email arrived at 12:05 p.m. Sunday, about 10 minutes before the explosion, but he didn’t see it until two hours later, when others told him Josh and the boys had been killed.