Up to $15 million (€15.6 million) was looted from the Municipal Credit Union in New York City immediately following September 11th, when computer failure caused by the collapse of the World Trade Centre allowed credit union members to withdraw unlimited sums from city ATMs, writes Conor Lally

The computer failure meant the credit union could not check if its members had sufficient funds on deposit to meet withdrawals after the towers collapsed. And it is now believed around 4,000 account holders withdrew more money than their accounts allowed.

The New York Post reported 66 people who withdrew at least $7,500 more than they had on deposit have been arrested. They face felony and grand larceny charges. And a further 35 are being sought for arrest.

The withdrawals began almost immediately after the Twin Towers collapsed. During the attack, the credit union, which is headquartered close to Ground Zero, lost its computer link to the New York Cash Exchange (a network of ATMs) and with it, its ability to check if its members had sufficient funds to cover withdrawals.

Mr Thomas Siciliano, the general counsel of the credit union, said the decision was taken not to shut down the 3,000-strong ATM system because the credit union believed by leaving the system running it was helping its 300,000 members through a difficult period.

"We did this at a time of crisis in the city because many of our members are firemen, policemen, and we felt at the time it was a necessary step to take to help settle down the city," said Mr Siciliano.

"We did not realise on the first day there would be this kind of loss."

The loss of the computer link was detected instantly but the system was not fully restored until mid November, around five weeks after September 11th. However, despite the loss of the computer link the credit union was still able to keep track of individual withdrawals.

It sent letters to all of those who exceeded their deposit level requesting the money back.

All of the 4,000 members of the credit union under investigation are understood to have overdrawn their accounts by more than $1,000 each. And those arrested are understood to have taken no opportunity to pay the money back. More than 540 members of the credit union made ATM withdrawals exceeding their balances by at least $5,000 and more than 1,700 exceeded their balance by at least $3,000.