More recently, real estate magnate Igor Olenicoff pled guilty in December 2007 to filing a false tax return.

FORBES: The World's Richest Tax Cheats

He's facing 40 months in prison for helping a client, Orange County "Billionaire with the Empty Pockets" Igor Olenicoff, hide money offshore.

FORBES: Informer

In 2006, in a case against billionaire Igor Olenicoff, the IRS succeeded in leveraging the Swiss banking giant, UBS, to release data on thousands of bank accounts held by Americans.

FORBES: FATCA: Giving More Tools to the IRS