PHOENIX -- A sex offender who posed as a 12-year-old boy to enroll in Arizona schools has pleaded guilty to seven criminal charges.

Neil Rodreick II has pleaded guilty to four counts of sexual exploitation of a minor, one count of fraudulent schemes, one count of failure to register as a sex offender and one count of simple assault, KPHO-TV in Phoenix reported.

Prosecutors said he will spend more than 70 years in prison with no chance of early release.

No victims of sexual abuse were found at the schools that 30-year-old Rodreick attended. But authorities said he once grabbed a girl's buttocks at a charter school where he was enrolled.

Authorities said he shaved and wore pancake makeup to appear younger, convincing teachers, students and administrators that he was a boy named Casey.

Rodreick was arrested in January 2007 when he tried to enroll in a charter school in Chino Valley as a seventh-grader. School officials became suspicious about his paperwork. At the time, he and convicted sex offender Brian Nellis were living with Lonnie Stiffler, 61, and Robert J. Snow, 43, another convicted sex offender.

Arizona authorities said Rodreick conned Stiffler and Snow into believing he was a young boy, and that Stiffler pretended to be his grandfather when he tried to enroll him at the school.

Rodreick was charged in Yavapai County with 15 criminal counts in all, including failing to register as a sex offender stemming from a 1996 Oklahoma incident in which Rodreick was convicted of lewdly propositioning a 6-year-old boy. Rodreick served more than five years in prison in that case.

Nellis, Stiffler and Snow have been indicted on various charges, including child pornography and forgery. Nellis and Snow were also charged with failing to register with authorities.

Federal charges against Rodreick also are possible stemming from more than 1,300 images of child pornography discovered on a computer Nellis rented, Gillock said.