A Casper man will likely spend over a decade in prison after admitting to sexually abusing a girl who was less than 13 years old at the time.

Forest Vincent Price, 35, pleaded guilty Tuesday in Natrona County District Court to two counts of second-degree sexual abuse of a minor.

Each charge carries a maximum sentence of 20 years in prison and a $10,000 fine.

At his arraignment in August, Price pleaded not guilty by reason of mental illness to three counts of first-degree sexual abuse of a minor and five counts of third-degree sexual abuse of a minor.

In exchange for Price's guilty pleas, the state agreed to recommend a 15- to 20-year prison sentence on each count, with those sentences running concurrently. The state also moved to dismiss six other charges against Price as contained in a third amended information.

Court documents say in October 2015, a Casper police detective began investigating alleged sexual assaults reported in Glenrock and Casper.

The victim reportedly said her first sexual encounter with Price -- her father's roommate -- was in June 2013. She was 12 years old at the time.

According to charging papers, further sex acts occurred in March and June 2015. The victim told the detective she broke off the "relationship" with Price because he was married and was going to have another baby.

Later in the investigation, Price reportedly admitted to the detective that the victim snuck out of her house to meet him four or five times. He denied, however, any sexual relationship.

An affidavit says Price agreed to take a polygraph test and said the results would show he never had sexual contact with the victim.

Less than two weeks later, the detective got a call from someone who said Price would not be coming in for the polygraph and would not be speaking to the detective without his attorney present.