A Hunter college student who worked as a self-described "boy-savvy" babysitter pleaded guilty yesterday to sexually abusing an 8-year-old boy. Jonathan Then, 20, was dragged out of class by police in May and charged with molesting four boys, ages 8 to 13. But prosecutors cut a deal to spare the children from testifying, and Then faces up to 12 years in prison on a single count of first-degree criminal sexual act.

Then, who graduated from a high school for gifted students in Connecticut, worked as a volunteer classroom aide to second-graders and third-graders at the fancy Dalton and Trevor Day schools on the Upper East Side, was employed at summer camps throughout the tri-state area, and was a babysitter for more than 20 families.

Investigators began looking into his conduct after he was accused of fondling an 8-year-old boy he was caring for in Brooklyn Heights; the victim's 11-year-old sister convinced him to tell their mother. At the time of his arrest, prosecutors said he had access to "hundreds of other young boys," but it's unclear how many were abused by the so-called "Manhattan Manny."