I wrote extensively about Birkenfeld's case during his prosecution and sentencing (here, herehere, and here). After complaining internally to UBS for two years, in June 2007 Birkenfeld voluntarily met with Justice Department prosecutors and an IRS Special Agent during three full days in which he provided unprecedented and voluminous information about UBS’s cross-border and offshore business activities, the UBS offices and private bankers that were directly involved, and the details of 19,000 UBS accounts for its American customers.