Washington (CNN) -- The IRS paid him $104 million for providing information as a whistle blower to prosecute banking giant UBS AG, and upended centuries of storied Swiss bank secrecy.
But for want of a cheap cab ride, former UBS banker Bradley Birkenfeld could end up back in prison after being arrested for driving while intoxicated in New Hampshire.
Birkenfeld, 48, was arrested July 20 by Portsmouth police conducting a sobriety check point. Birkenfeld, who listed a Rye, New Hampshire, address, is scheduled for trial on Nov. 12.
His federal probation officer told CNN that he is aware of the arrest and that if Birkenfeld is convicted it would be a violation of terms of his supervised release after serving 30 months in prison.
He was originally sentenced to 40 years after pleading guilty to defrauding the United States, but was released early for good behavior.
Under terms of his release, Birkenfeld is barred from "excessive use of alcohol."
Federal prosecutors are monitoring the DUI case and are weighing whether to recommend Birkenfeld be found in violation of those terms, according to a person familiar with the matter.
A Justice Department spokesman declined to comment. An attorney representing Birkenfeld didn't respond to a request for comment, and Birkenfeld couldn't be reached.
Justice Department prosecutors used documents and other information provided by Birkenfeld to prosecute UBS and some of its top bankers for aiding tax evasion by U.S. offshore banking customers.
Birkenfeld claims to have provided U.S. authorities hundreds of confidential UBS documents on about 19,000 customers.
UBS paid $780 million in 2009 under a deferred prosecution agreement with the Justice Department to settle the charges.
Birkenfeld's probation officer said if he is convicted a judge could order that he be sent back to prison or be subject to additional supervision requirements.
The probation office hasn't decided what course to take.
"Despite this being a high profile case, we'll treat this like any other case," said the probation officer, who asked not to be identified by name.