NY- He wore impeccable suits, always had a beautiful woman on his arm and peddled multimillion-dollar mansions in the playground of the rich and famous.

But police say that behind Hamptons real estate broker Matthias von Wrede’s slick exterior lurked a sick secret – an obsession with child pornography.

When they raided his Sag Harbor home Monday night they uncovered hundreds of CDs holding such vile images as a toddler in a diaper being molested by an adult.

“The collection we have now is extensive,” Suffolk County Police Detective Lt. Peter Cilento said yesterday.

“Several images depicted prepubescent males and females in bondage and in various sex acts.”

Von Wrede, 34, is managing partner of the Southampton office of Engel & Volkers, a German-based real estate firm that’s among the largest in Europe.

It specializes in luxury properties, like the $5 million estates and $200,000 summer rentals on display in the window yesterday.

In keeping with his company’s reputation, von Wrede cut a debonair figure in the Hamptons.

“You always see him with beautiful women,” said Brian Brady, whose architectural firm is next door to the brokerage.

“He’s always well-dressed – a suit every day – and always well-spoken,” said Adam Batcheler, who runs the Village Tea Shop, where von Wrede ate breakfast and lunch most days.

Suffolk cops said they were led to von Wrede after Yahoo! notified state investigators that someone had uploaded kiddie porn onto its site.

When von Wrede, who is originally from Munich, was arrested at his rented saltbox-style home on Madison St., he seemed surprised, cops said.

“He was very passive, very timid, very apologetic,” said the arresting officer, Jeffrey Proctor of the Sag Harbor Police.

He called his girlfriend, Louise Erlandsson, a blond knockout with a Scandanavian accent, from the police station to break the news.

“He was crying,” Proctor said.

Von Wrede was charged with possession of child pornography, which carries a maximum sentence of 1-1/3 to 4 years.

Bail of $250,000 was posted last night by Erlandsson. The address she gave is the same as wealthy retired German businessman Jurgen Friedrich, who buys and sells property to European expatriates through von Wrede.

Friedrich declined comment last night at his gated estate. Von Wrede’s attorney, Colin Astarita, also refused to comment.