At a rate of one or two a week, Swiss banks are doing what was once unthinkable: revealing to the world how they helped wealthy Americans cheat on their taxes.

Once bastions of secrecy, 41 Swiss banks signed amnesty agreements this year with the U.S. Justice Department that required disclosing the tricks they used to help customers hide assets, naming bankers and middlemen who enabled them and detailing the flow of untaxed money. They've also prodded thousands of reluctant Americans to disclose accounts hidden from the Internal Revenue Service.

The flood of information is now giving U.S. investigators intelligence to try to build new cases against individuals and institutions in other countries, said Caroline Ciraolo, the Justice Department's top tax prosecutor. Financial institutions in Singapore and Israel are possible targets, according to lawyers and prosecutors.

"The money is moving out of Switzerland to a variety of jurisdictions," said Ciraolo, an acting assistant attorney general. "We're following leads and following the money, wherever that leads us."

The Swiss amnesty program is part of a tax evasion crackdown that grew after 2009 when Switzerland's biggest bank, UBS Group AG, paid $780 million to avoid prosecution, and the U.S. began criminal investigations of 14 other banks, including Credit Suisse Group AG.