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The husband of missing Utah mother Susan Powell is temporarily losing the right to care for his children after officials questioned whether he is responsible for his wife's disappearance.

Josh Powell was in court Wednesday battling for custody of the couple's two sons, despite an accusation that he was the subject of a child porn investigation.

A Washington state judge said that there is reasonable cause to believe the boys cannot be safely returned to the home of Josh Powell. Judge Kathryn Nelson ordered that the boys, ages 4 and 6, stay with Susan Powell's parents, Chuck and Judy Cox, although Josh Powell will have the ability to visit.

Powell has not been charged in his wife's disappearance.

During a separate hearing Tuesday, assistant attorney general for Child Protective Services, John Long, accused Josh Powell of being the subject of a pornography and voyeurism investigation, Komo News reports. Long also voiced concerns about Powell, including that he has been uncooperative with law enforcement.

"It leads the state to believe that he is responsible for her disappearance," Long said.

Police said they were trying to establish whether Josh Powell had anything to do with the thousands of images his father Steve Powell -- who is currently in jail awaiting trial -- allegedly captured of women and girls without their knowledge, according to the Salt Lake Tribune.

Steve Powell pleaded not guilty to the child pornography and voyeurism charges in court last Friday and was remanded in custody awaiting trial.

Chuck Cox filed for custody of the children the same day, arguing that his grandsons, who lived at Steve Powell's home in Puyallup, Wash., with their father, were at risk living in the same home as their now-jailed grandfather.

More details emerged Wednesday about Steve Powell's past in a 1992 divorce case from Spokane County. Case documents reviewed by The Associated Press show Steve Powell's ex-wife accused him of keeping pornography, damaging his children's respect for marriage and inappropriately discussing sex issues with the kids.

Terri Powell wrote in the divorce papers that Steve Powell talked of teaching his children about birth control methods when they were as young as 9 years old. Terri's sister, Becky Mulcahy, wrote in the documents that Steve Powell told her that he had shown his youngest children books about sexual intercourse when they were 6 and 8 years old.

Terri Powell said her husband viewed people as animals and that they should be able to have sex with anyone at any time. She recalled a conversation in which Josh referred to a girl his brother, Johnny, liked. "All she is good for is her body, right Dad?" Terri recalled Josh saying.

"Yeah, that's right," Steve Powell replied, according to the declaration.

Terri Powell also said Steve Powell kept pornography in the home and that he visited pornography shops.

Jennifer Graves, Josh Powell's sister, said in an interview with The Associated Press that she broke off ties with her father in part because of his problems with sex and pornography. She recalled going on a business trip with her father when she was about 11 years old and that he viewed a pornographic video while she was with him.

"Looking back, I wonder if he was willing to do that with a 10-12 year girl -- his daughter -- in the room, what else would he be willing to do?" she said.

Steve Powell has pleaded not guilty to 14 charges of voyeurism and one of possession of child pornography. He remains jailed on $200,000 bail. Prosecutors said that for at least a decade, he had been secretly filming women, including Susan Powell, and that he shot footage of two young neighbor girls as they took baths and sat on the toilet.

Josh Powell immediately denied the child porn accusation Tuesday, telling the judge he never saw any pornography at the house and added that neither he nor his family would be posting bail for their father.

He said he had provided a safe and happy home for his children since his wife's disappearance and argued that the children would be safer with him than the Cox family, who he accused of having a "clear hatred" for him.

Powell is a person of interest in his wife's disappearance, but he has not been charged and insists he did nothing wrong. An assistant attorney general said during Wednesday's hearing that the state believes Powell is responsible for his wife's disappearance.

Powell advocated without an attorney that it was in the best interest of the children for him to keep caring for them.

Susan Powell was last seen on Dec. 7, 2009, when Josh Powell said he left their home in West Valley City, Utah, to take their two sons, then age 2 and 4, camping in freezing conditions. Josh Powell has been the only named person of interest in the case, but he has never been arrested or charged.

Utah authorities searched an area near Topaz Mountain, 30 miles southwest of Simpson Springs, where Josh Powell said the camping trip took place. So far, however, they have only uncovered pieces of charred wood they believe may have been used to burn human remains.

Newscore and The Associated Press contributed to this report.