More than 12 years ago, a major U.S. bank decided not to do any business with a Luxembourg-based institution called the Bank of Credit and Commerce International.

One of the American executives recalls that something about BCCI just didn’t add up. “They were reluctant to provide information about the sources and uses of funds,” he said last week. “We got bad vibes from them … so we just put them on our internal blacklist.”

A lot of other people got bad vibes from BCCI, and among bankers it acquired the nickname of “Bank of Crooks and Criminals.” But it took a dozen years for regulators overseeing BCCI’s far-flung empire in Britain, Luxembourg, the Cayman Islands and elsewhere to reach the same conclusion. // In the interim, BCCI wove what its auditors, Price Waterhouse, belatedly discovered and now describe as “probably one of the most complex deceptions in banking history.”

BCCI made phony loans, concealed deposits, hid huge losses, and was the bank for a host of shady customers ranging from terrorists and spies to drug runners and dictators.  //

The unmasking of the bank has provoked a slew of questions about how a financial scandal of such magnitude was covered up for so long while 1.2 million depositors, most of them from Third World countries, entrusted their money to BCCI. Where were the regulators? What blinded the auditors? To what extent were various intelligence agencies, including the CIA, involved? What were BCCI’s links to drug kings and dictators?

According to British authorities, BCCI committed fraud on a grand scale: keeping separate books for a “bank within the bank” that handled illegal transactions, making a $32 million payoff to silence one of its own managers, using clients’ accounts to hide its own losses, and shuffling money among different affiliates to disguise the bank’s true financial condition.

On July 5, the Bank of England exhausted efforts to clean up the bank and shut its doors, alleging the fraud was so “massive” that BCCI could not be reformed. “The culture of the bank is criminal,” said Robin Leigh-Pemberton, a governor of the Bank of England.

Among the unsolved mysteries: Where did the estimated $5 billion hole in the bank’s balance sheet go?… (etc.)