A Troy man accused of sexually abusing a boy faces 20 years behind bars after striking a deal with prosecutors.

Nathan Michael Miller, 42, pleaded guilty to a single felony count of sexual assault, victim younger than 16, on May 17. In exchange, prosecutors agreed to drop a sexual abuse of children charge against him.

Miller’s sentencing in Lincoln County District Court is scheduled for June 21. Prosecutors will recommend that Miller receive a 45-year sentence with the Montana State Prison with 25 years suspended. He will be required to undergo sex offender treatment before becoming eligible for parole.

Authorities in Lincoln County began investigating Miller after an Idaho-based therapist alerted them to a 12-year-old client who reported performing sexual acts in front of him, according to court documents. The victim said that Miller had shown him videos of other minors engaging in sexual acts, court documents said.

In an affidavit, Detective Dave Hall described contacting the child’s grandmother. She told investigators that Miller was close with her deceased son and the two families occasionally got together.

Last July, Hall drove to Idaho to meet with the minor. According to court documents, the boy readily acknowledged that Miller had “molested” him. The first incident occurred two years earlier, court documents said. The minor allegedly told authorities that he woke up to Miller performing a sexual act on him.

A second incident occurred in Miller’s apartment in Montana, court documents said. The boy recalled Miller calling him back to the bedroom and showing him pornography. He then began performing sexual acts on himself and the boy, court documents said.

In the affidavit, Hall wrote that Miller had previously come to the attention of authorities. The sheriff’s office had received cyber tips of Miller downloading child pornography. Officials in Boundary County, Idaho, also passed along a cyber tip linking Miller’s phone to child pornography, court documents said.