Reporting from Mexico City— Money launderers for ruthless Mexican drug gangs have long had a formidable ally: international banks... Banking powerhouse Wachovia Corp. last year agreed to pay $160 million in forfeitures and fines after U.S. federal prosecutors accused it of "willfully" overlooking the suspicious character of more than $420 billion in transactions between the bank and Mexican currency-exchange houses — drug money HSBC Bank, is being monitored by U.S. regulators after a probe last year focused on bulk cash that the bank's U.S. branch received from Mexican exchange houses, money suspected to be drug proceeds....
