DHAKA, Bangladesh — It was no secret in this land of crushing poverty and disease that the Bank of Credit & Commerce International and its dynamic chairman, Aga Hasan Abedi, had a special relationship with Bangladesh and its long-serving dictator, President Hussain Mohammed Ershad.

But few knew just how special.

When Ershad's relatives needed jobs, for example, Abedi quietly hired them for high-paying senior management positions at key BCCI branches in Hong Kong, Britain and Canada.

When Abedi needed a diplomatic cover to bring BCCI into the lucrative banking market in the oil-rich sultanate of Brunei, Ershad dipped into his nation's meager budget, hired one of BCCI's most flamboyant bank managers to serve as Bangladesh's first ambassador to Brunei and opened a new Bangladeshi embassy in the sultanate. It functioned more like a BCCI sales office than the foreign mission of a fellow Islamic nation.

And finally, when Ershad, in his last years in power, needed help in plundering his impoverished nation of what prosecutors now contend was hundreds of millions of dollars in kickbacks and commissions on foreign-aid projects, Abedi's bank was there.

It was ready and willing to funnel the dictator's ill-gotten wealth through its vast international network of bank branches into secret Ershad accounts in Europe, the Caribbean and the Far East, according to documents and the chief prosecutor who is pursuing the case against the now-jailed Ershad on more than 50 counts of corruption.

"They have plundered this country--both of them," Bangladesh's Atty. Gen. Aminul Haq lamented in a recent interview, in which he detailed for the first time how Ershad allegedly used BCCI to rake in kickbacks worth more than $1 billion--the equivalent of the entire annual budget of this nation of 100 million people.

"This bank, this BCCI, was a smuggler's paradise," the prosecutor said. "They were the bankers of all the smugglers and the corrupt people here. . . . Of course they helped ruin us."

According to documents obtained by The Times and information from dozens of interviews with BCCI officers, government officials and private businessmen throughout South Asia, it was from behind Abedi's self-styled veneer of charity and the boosting of the Third World--which the Pakistani marketing wizard used to promote himself and his bank as champions of the poor and oppressed in more than 70 nations worldwide--that BCCI did far more harm than good to Third World nations like Bangladesh.