Phoenix ? A sex offender who posed as a 12-year-old boy to enroll in Arizona schools has pleaded guilty to seven criminal charges and will go to prison for more than 70 years, a prosecutor said Wednesday.

Authorities didn’t find any victims of sexual abuse at the schools 30-year-old Neil Havens Rodreick II attended. But when Rodreick’s ruse was discovered in January 2007, they found an extensive collection of child pornography at his home.

Rodreick originally faced 28 counts but pleaded guilty to only a quarter of them Friday in Yavapai County Superior Court, according to a plea agreement document. Rodreick pleaded guilty to four counts of sexual exploitation of a minor stemming from the pornography, and one count each of failure to register as a sex offender, fraud and simple assault.