Investigators and bank regulators say Kabul Bank is also tied to the inquiry into New Ansari, the money-transfer firm, or hawala, that is suspected of moving billions of dollars out of the country for Afghan politicians, drug traffickers and insurgents. Kabul Bank used the firm, whose dealings are nearly impossible to track, to transfer at least $60 million out of the country, a bank shareholder said.

For a bank to use a hawala to move money is inherently suspect, investigators say, because a financial institution like Kabul Bank already has the means to transfer the money electronically. Electronic transfers are easier for regulators to follow.

Neither Mr. Farnood nor Mr. Frozi could be reached for comment on Tuesday.

Bank regulators emphasized that the Afghan government had not taken over Kabul Bank. The regulators said they were worried that the bank would not be able to cover a run of withdrawals from nervous creditors.

Afghan officials and businessmen said other financial institutions here might be affected by similar troubles; the shareholders of other banks also indulge in the practice of lending large sums of money to themselves.

In interviews, Afghan officials and businessmen described Kabul Bank as Mr. Farnood’s personal fief, which he used to reward himself, shareholders and political allies who could advance his financial interests.

First among the beneficiaries was Mr. Farnood himself, the officials said. He invested about $140 million of the bank’s money in the real estate market in Dubai in the United Arab Emirates, said Mahmoud Karzai, the president’s brother and a Kabul Bank shareholder. Among those properties were more than a dozen multimillion-dollar villas in Mr. Farnood’s name, some of them on Palm Jumeria, an island off Dubai’s coast, Mr. Karzai said.

The Dubai real estate market collapsed in 2008, wiping out much of Mr. Farnood’s investment and leaving Kabul Bank with the losses. A senior Afghan banking official said that the bank’s estimated losses were believed to be about $300 million, with assets of about $120 million.