EVERETT — A Snohomish man is being accused of sexually assaulting the daughter he and his wife adopted after she was removed from what is described as a “polygamous clan” in Utah.

The criminal investigation into the allegations also has resulted in a complaint to the state Department of Health against a therapist who reportedly recommended that the defendant, his wife and the then-15-year-old girl all sleep in the same bed as a way to bond.

A month after the family took the therapist’s advice, the man allegedly began sexually assaulting the girl, Snohomish County deputy prosecutor Adam Cornell wrote in charging papers.

The man, 42, is charged with child rape and molestation, and incest. He pleaded not guilty to the charges Friday in Superior Court.

He was being held on $100,000 bail and ordered not to have any contact with his daughter. The man faces up to 8 1/2 years in prison if convicted as charged.

The Herald is not naming the defendant in order to protect the young woman’s identity.

The case came to the attention of authorities in July. A few months earlier, the now 20-year-old woman disclosed to a mental health professional that her father started sexually assaulting her in 2006, shortly after she was adopted.

Court papers say she was placed in foster care after spending most of her childhood in a polygamous group, where she was abused. She met the defendant and his wife shortly after she was taken away from her birth parents.

When the defendant moved from Utah to Snohomish, he and his wife began visitations with the girl, intending to adopt her.

They were aware that “she was an emotionally fragile and vulnerable child,” Cornell wrote.

In Washington, the girl and adoptive parents began meeting with a therapist to address what the therapist described to police as the girl’s “abandonment and attachment issues,” court papers said.

That’s when the therapist reportedly recommended that they all sleep in the same bed together. During the course of the investigation, police interviewed the therapist who confirmed that she’d suggested such “attachment therapy,” Cornell wrote.

Earlier this month, the detective who investigated the case filed a formal complaint with the state against the therapist.

In the criminal case, the defendant is accused of sexually assaulting the teen starting about a month after she and her adoptive parents all began sleeping in the same bed. She later told detectives that the sexual abuse lasted until she left for college in 2010.

The woman told investigators that she was forced to have sex with her father every week. When she attempted to resist, he reportedly threatened to send her back to her birth parents. He said that she would be married off into a polygamous family, court papers said. The man also reportedly threatened to kill himself if she told anyone about the abuse.

Detectives last year obtained a judge’s permission to record telephone conversations between the woman and the defendant. During two telephone conversations the woman confronted the man with allegations of sexual abuse. He reportedly said, “I understand where you are coming from, I can’t argue with what you said … there’s no argument to be had,” Cornell wrote.

Diana Hefley: 425-339-3463; hefley@heraldnet.com.