Describing what could be scenes out of a spy movie, Senate investigators alleged Tuesday that Swiss banking giant Credit Suisse went to extreme lengths to help wealthy Americans evade U.S. taxes.

In one instance, investigators said a Credit Suisse banker met with a client for breakfast and handed the client a copy of Sports Illustrated with the customer’s bank statements hidden inside.

The client told investigators that another time, the client met the banker in Switzerland in a room accessible by a remote-controlled elevator with no buttons.

The Senate permanent subcommittee on investigations said that in 2006, before the U.S. began to crack down harder on secret Swiss bank accounts, Credit Suisse serviced more than 22,000 U.S. customers and that data suggest “the vast majority” were “undeclared” to the Internal Revenue Service. The accounts held $10 billion to $12 billion.

The findings were released in a 175-page bipartisan subcommittee report after a two-year investigation into the practices of Credit Suisse and other Swiss banks.

The subcommittee will hold a hearing on the issue on Wednesday. Officials from Credit Suisse and the U.S. Justice Department are scheduled to testify.

The subcommittee first began investigating the controversy in 2008 with a hearing on another major Swiss bank, UBS, which acknowledged improper supervision of accounts held by Americans. It was later charged by the Justice Department and turned over records on 4,700 undeclared U.S. accounts, paying a $780 million fine in a settlement. 

Since the UBS case, Credit Suisse has closed about 18,900 accounts of U.S. customers as part of a formal review, while retaining 3,500 accounts, the subcommittee report said.

But despite assurances of more cooperation by the banks and Swiss authorities since 2011, the subcommittee said, Credit Suisse has turned over the files on just 230 U.S. customers under a U.S.-Swiss tax treaty.

The report also accused the Justice Department of “lax” enforcement of tax evasion laws with Credit Suisse and other Swiss banks. The subcommittee wants the department to get more aggressive in investigating and prosecuting cases. 

“Unless DOJ is willing to use available U.S. legal remedies to obtain those U.S. client names, many of the most egregious cases of tax evasion using hidden offshore accounts will escape accountability,” the report said.

The panel’s chairman, Sen. Carl Levin, (D-MI), and ranking Republican, Sen. John McCain, (R-AZ), said that aside from the issue of basic tax fairness, payments and penalties by wealthy Americans using Swiss banks to hide cash could help fund important government programs.

An IRS initiative for U.S. tax cheats who voluntarily disclose their offshore accounts to avoid prosecution has so far generated $6 billion in back taxes, interest and penalties from 43,000 taxpayers, they noted.

A Justice Department spokesperson defended the department’s record in tracking down U.S. tax evasion, especially through Swiss banks.

“We have acknowledged that as many as 14 Swiss financial institutions are currently under investigation, and we won't hesitate to indict if and when circumstances merit,” she said.

She added that the prospect of U.S. prosecution “has been forceful enough to cause 43,000 taxpayers to self-report and pay nearly $6 billion in taxes and penalties. Additionally, more than 100 Swiss financial institutions have applied for a program where they fully disclose their illegal conduct, cooperate and pay steep penalties.  That program will help the department root out tax evasion throughout the world.  And since its announcement, we’ve seen an influx of new voluntary disclosures from account holders, who recognize its effectiveness.”

She said that since 2009, the department has charged 73 account holders and 35 bankers and advisors with offenses related to offshore tax evasion.

Last week, Credit Suisse agreed to settled charges by the U.S. Securities and Exchange Commission that it provided clients with cross-border brokerage services and investment advice without registering with the agency. It agreed to pay $196.5 million and admit wrongdoing in the case.

In January, the Wall Street Journal reported that Credit Suisse and U.S. officials were in settlement talks over the bank's alleged tax evasion practices and that a deal could include more than $800 million in fines and payments.

A spokesperson for Credit Suisse declined to comment on the subcommittee hearing and report.

Peter Barnes joined FOX Business Network (FBN) in September 2007. He serves as FBN's senior Washington correspondent.