A man could spend the rest of his life behind bars after admitting Wednesday morning in Natrona County District Court to four felony charges stemming from a young girl's claim that he had "basically been raping [her] for a long time."

Aaron Andrew Rushing, 38, pleaded guilty to three counts of first-degree sexual abuse of a minor and one count of possession of child pornography. He could now face 75-160 years in prison at his sentencing hearing, which will be held at a later date.

In exchange for his guilty pleas, Assistant District Attorney Mike Schafer agreed to drop the remaining six counts -- including charges of first- and second-degree sexual abuse of a minor -- filed in a second amended information.

Court documents say a 15- or 16-year-old told Casper police in February he had accidentally found child pornography on a flash drive belonging to Rushing.

The child pornography allegedly depicted the teenager's relative, who was 12 years old when she suffered the abuse Rushing admitted to Wednesday.

In an interview at the Children's Advocacy Project in Casper, the victim detailed numerous sexual assaults that happened in a camper and in the basement of a home in Natrona County, according to an affidavit.

An investigator with the Natrona County Sheriff's Office interviewed Rushing that same day. Rushing allegedly spoke at length about having pornographic images of children on a USB drive.

Rushing also reportedly detailed sexual contact and sexual intrusion he had with the victim from February 2015 through December 2016, according to charging papers.