A onetime informant against the mob claims his former Ivy League-educated business partner has attempted to shake him down along with several prominent law firms, businessman Donald Trump and even a federal prosecutor.

Salvatore Lauria, who turned against alleged Mafioso after he was nabbed in a securities fraud in the 1990s, claims in a complaint filed in Manhattan Supreme Court that Jody Kriss, his onetime partner in the Bayrock Group real estate development firm, is engaged in a “billion-dollar shakedown.” Lauria is represented by Nader Mobargha and Michael Beys of Beys Stein Mobargha & Berland, which includes itself as one of the victims.