TACOMA, Wash. (AP) — Authorities in Washington state say the father-in-law of a Utah woman who went missing in 2009 has died.

The Pierce County Sheriff’s Department said Steven Powell died Monday at St. Joseph’s Hospital in Tacoma, a year after he completed his prison sentence for possession of child pornography.

Steven Powell is the father of Josh Powell, who is believed to have killed his wife, Susan Powell, in Utah before moving to Washington state, where he killed himself and his two young sons in an explosive fire at their Pierce County home in 2012.

Investigators found the child pornography, consisted of images Steven Powell took of the neighbor girls in various states of undress, while searching his home as part of the investigation into Susan Powell’s disappearance.