Washington (CNN) -- A former Credit Suisse banker pleaded guilty on Tuesday to fraud charges, setting the stage for prosecutors to challenge claims by the Swiss bank that helping wealthy Americans evade taxes was the work of a few rogue bankers.
Andreas Bachmann, one of the eight former Credit Suisse bankers under indictment, entered his plea in federal court in Alexandria, Virginia. He will be sentenced in August and could face up to 46 months behind bars.
As part of his plea deal, Bachmann is expected to cooperate with an ongoing Justice Department investigation of Credit Suisse.
His cooperation is expected to increase the scrutiny of assertions made by Credit Suisse CEO Brady Dougan, who two weeks ago expressed regret at a Senate hearing that the bank helped rich U.S. clients hide billions of dollars in assets from the IRS.
He claimed that the wrongdoing was limited to a few bankers who are indicted and was not activity encouraged by Credit Suisse.
Bachmann was arrested on Tuesday on a 2011 warrant, one of a handful of Swiss bankers to ever face U.S. charges because Switzerland doesn't consider tax evasion a crime and won't turn over its citizens to face such charges.
He was released on $200,000 bond.
An attorney for Bachmann didn't immediately respond to a request for comment. A spokesman for Credit Suisse didn't immediately respond to a request for comment.
A recent investigation by the Senate Permanent Subcommittee on Investigations found that Credit Suisse held as much as $12 billion in assets for 22,000 U.S. clients, up to 95% of which was hidden from the IRS.
Prosecutors have spent years pursuing the Credit Suisse inquiry.
Lawmakers recently chastised the Justice Department for not moving more aggressively against the financial institution and 13 other banks under criminal investigation for aiding tax evasion.
The indictment against Bachmann and the other former Credit Suisse bankers alleges they helped customers move funds to offshore tax havens using specially created shell companies and other entities to hide assets from the IRS.
According to the indictment, Bachmann met with his Credit Suisse clients to help advise them on how to move their assets when the United States began putting pressure on Swiss banks to stop aiding tax evasion.
The Senate report described methods worthy of a spy novel that Credit Suisse bankers used to help their wealthy American clients stash money away.
The bank opened a special Zurich airport branch so customers could fly in, meet their private bankers and quickly hit the slopes, Senate investigators said.
VIPs would use a secret elevator operated by remote control to be whisked to private banking suites. And bankers used sparse meeting rooms and avoided sending account statements and leaving paper trails, the Senate report said.
One banker slipped a client's bank statement between the pages of a Sports Illustrated magazine during a meeting.
Dougan said he was "extremely dismayed by the conduct" of the few bankers he blamed. He and other executives testified that they're cooperating as much as possible with the U.S. investigation, given the limitations of Swiss law that require client confidentiality.
His testimony contrasted with that of executives from rival Swiss bank UBS five years ago. That bank apologized and accepted blame for the wrongdoing of its bankers.
In recent months, Credit Suisse has discussed settling charges with the Justice Department by paying about $800 million. Sens. Carl Levin and John McCain, who oversaw the Senate hearing two weeks ago, called that sum too small given the allegations.