The Libby man accused of raping a child in January faces 15 years behind bars after striking a plea deal with prosecutors last month.

Cody Joseph Mattis, 28, pleaded guilty to a single count of sexual assault in Lincoln County District Court on June 7. He initially pleaded not guilty to that charge as well as two counts of sexual intercourse without consent. Prosecutors ultimately dropped the latter charges as part of the plea agreement.

Authorities arrested Mattis while responding to a disturbance in Libby on Jan. 17. According to court documents, Lincoln County Sheriff’s Office deputies headed to his home after a woman reported catching her boyfriend raping an 8-year-old child.

In an affidavit, Deputy Steve Short recounted talking with Mattis after arriving at the scene. Mattis, he wrote, admitted to sexually assaulting the child, a relative.

Short arrested Mattis shortly thereafter and took him to the Lincoln County Detention Center, where he has been held on a $100,000 bond while awaiting trial.

Investigators later followed up with the woman who contacted authorities. She told Short she installed a camera in the bathroom after suspecting the child was suffering sexual assault at Mattis’ hands. On the night of his arrest, she got an alert that someone was using the bathroom.

She began streaming the video and saw him place the victim on the counter before penetrating her, court documents said. The woman recounted running into the bathroom, yelling and punching him. During the scuffle, she saw that he had his genitals exposed, court documents said.

The woman phoned 911 soon after.

According to the court documents, the victim confirmed that Mattis had penetrated her with his finger to another deputy investigating the incident.

As part of the plea deal, prosecutors will recommend Mattis serve 15 years of a 35-year sentence with the Montana State Prison. The remainder will be suspended. Mattis must complete two phases of sex offender treatment before becoming eligible for parole, according to the terms of the deal.

Mattis’ is expected to return to court on July 12 for sentencing.