POPULAR MANHATTAN MANNY HAS NEW YORKS UPPER CRUST IN A FRENZY!

Parents in some of the city's swankiest neighborhoods were in a panic Friday night after a "Manhattan Manny" who called himself an "amazing big brother figure" was charged with molesting four boys.

A prosecutor warned that Jonathan Then "had access to hundreds of other young boys" in recent years, both in New York City "and beyond."

Among other things, Then worked as a volunteer classroom aide with second- and third-graders at two elite private schools, Dalton and Trevor Day School.

The 21-year-old suspect also worked at numerous summer camps, day camps in New York City, Connecticut and "at least one sleepaway [camp] in New Hampshire," Manhattan assistant district attorney Rachel Ferrari said.

On a Web site, Then described his current job as "a live-in nanny for two boys in Tribeca, a job that ends June 2009 when they are leaving the city."

The accused pervert is especially attracted to 8- to 10-year-old boys, "and boys only," a law enforcement source said.

He was first arrested on April 20 and charged with molesting a Brooklyn boy. He was out of jail three days later on bail, and it is unknown what contact with children he has had since then.

On Thursday, he was yanked out of a classroom at Hunter College, where he is a junior majoring in early childhood education, and arrested on charges of molesting three Manhattan boys. Those incidents occurred before April 20.

Then appeared in Manhattan Criminal Court Friday, where he was charged with five counts of sexual assault against a child, 14 counts of sexual abuse, possession of child pornography, and other charges that could send him to jail for life.

Dressed in jeans and a hooded sweatshirt that had Brooklyn written across the chest, Then stood impassively as Ferrari laid out the charges against him. He was ordered held without bail and placed on suicide watch.

There were loud gasps from the gallery as Ferrari described some of the perverted images of adults having sex with boys that were found on Then's computer.

On what appears to be his "Manhattan Manny" Web site, Then boasted that he had "worked for some celebrities and high profile families" whom he met by word of mouth.

In an ad Then placed on another Web site, he posted a photo of himself hugging a child and described himself an "Upper West Side native." On another site, Then described himself as "Very boy-savvy."

Then attended Simsbury High School in Simsbury, Conn., under a program designed to help high-achieving minority students from poor city school districts.

Detectives got on Then's trail in April, when he was arrested in Brooklyn for molesting an 8-year-old boy, Ferrari said.

"Each family we've spoken to has given us names of other families who hired the defendant, and whose homes the defendant has been in," said Ferrari.

Ferrari said Then "has admitted in detail to sexually abusing all three boys in [Friday's] complaint."

Pam Clarke, head of the Trevor Day School, said Then "was never alone with the kids." She said they did a background check on Then "and his was completely clean."

Dalton issued a statement saying Then volunteered for six months last year and it did not appear he did anything improper.

Investigators also have alerted officials at Camp Winaukee on Lake Winnipesaukee, N.H., where Then worked last summer.

PIC OF JONATHAN THEN: