Frederick Harder, 38, is held at the Ottawa County jail without bond following his Monday indictment for the crimes.
He was first arrested Nov. 27, only a day after the victim told sheriff's deputies about the assaults.
"She disclosed the abuse to a friend, then a relative, and the relative brought her to the sheriff's office to report the crime," Ottawa County prosecutor Mark Mulligan said.
When the victim told deputies about the crimes and that she had found child pornography on Harder's computer, they decided to search his home in the 2000 block of East State Road.
When deputies told him about the allegations at his mother's house and asked him for permission to search, he agreed.
Deputies drove Harder to his home and read him his Miranda rights on the way.
"(He) said several times that he was shocked by the accusations," according to a police report.
The trailer Harder lived in was filthy, piled high with clothing and trash, and smelled of feces and rotting food.
Harder signed a form allowing deputies to search the residence. They seized bedding, a used condom, five CDs, a VHS tape labeled "Tom's Porn," a laptop and computer tower.
The next day, deputies arrested him for tampering with evidence and he has been in jail ever since.
The tampering with evidence charge has since been dropped, but Harder remains behind bars for the alleged crimes.
An Ottawa County grand jury indicted him this week on 37 counts of rape and 36 counts of sexual battery.
He remains in jail without bond.