Imprisoned al-Qaida operative Zacarias Moussaoui, who was accused of being a potential hijacker in the Sept. 11 plot, has apparently volunteered his services as an expert witness on terror financing in Brooklyn federal court suits against Arab Bank.

A jury on Sept. 22 ruled the Jordanian bank liable in 24 attacks in Israel and the Palestinian territories in the early 2000s, finding it was willfully blind to dealings that aided Hamas.

A week later, a handwritten note signed by Moussaoui with a return address at the federal supermax prison in Florence, Colorado, where he is serving a life sentence, arrived in the clerk's office. The letter, docketed last week, says he heard about the verdict on Fox News.

"I want to testify against financial institution such as the Arab Bank, Saudi American Bank, the National Commercial Bank of Saudi Arabia" and several Saudi princes, Moussaoui wrote, "for their support and financing of Usama bin Laden and al-Qaida."

Moussaoui, who said he previously tried to make his offer to help plaintiffs in a Manhattan federal lawsuit brought by Sept. 11 victims, asked the clerk to forward the letter to the judge and the plaintiffs in the case "out of courtesy and ethic."

His chances of appearing in court any time soon, however, seem slim.

"Doubtful," said one lawyer suing the bank, who declined to comment on the record.

And Arab Bank, in a statement, questioned the public posting of the letter.

"It is troubling that the Court would give credence to the irrelevant ramblings of a person without any connection to the case by posting his letter on the docket," the bank said. "In fact, it is quite puzzling how this could have happened."

Moussaoui, a French citizen who had attended al-Qaida training camps in Afghanistan, was arrested a few weeks before Sept. 11, 2001, on immigration charges after his behavior at a flight training school raised suspicions.

Officials later suggested that he might have intended to join the 19 Sept. 11 hijackers as the "20th hijacker," or was present in the United States as a backup.

Prosecutors sought his execution on the theory that lies he told after his arrest kept the plot from being detected, but a federal jury in Virginia rejected the death penalty. He is serving life on six counts of conspiracy.