PRESCOTT, Ariz. —  Authorities investigating a 29-year-old sex offender suspected of repeatedly enrolling in schools as a 12-year-old boy said Thursday they seized a video showing him engaging in sex acts with a child.

Investigators were trying to determine the identity of the juvenile shown in the video with Neil Havens Rodreick II, a convicted sex offender from Oklahoma, said sheriff's spokesman Scott Reed.

Rodreick, who looks youthful, was arrested last week after officials at a school in Chino Valley, about 90 miles northwest of Phoenix, became suspicious when he tried to enroll as a seventh-grader.

Besides the video, CDs, a computer and paperwork were seized during searches of a Chino Valley home where Rodreick lived with Lonnie Stiffler, 61, Robert Snow, 43, and Brian Jay Nellis, 34.

The four men were arrested Jan. 18, the day after Stiffler, posing as Rodreick's grandfather, allegedly attempted to enroll Rodreick in the Mingus Springs Charter School as 12-year-old "Casey Price."

The sheriff's office said Rodreick conned Stiffler and Snow into believing he was a young boy.

All four were charged with conspiracy to commit fraud and conspiracy to commit forgery, and Rodreick, Snow and Nellis were charged with failing to register as sex offenders.

Rodreick also is charged with other counts, including misdemeanor assault for an incident involving a girl. He remains in the Yavapai County jail.

Officials at another school, the Imagine School at Rosefield in the Phoenix suburb of Surprise, said Rodreick attended class from August through November before they dropped him for poor attendance. He spent a total of 50 days in class, and apparently did not raise concerns.