WASHINGTON -- Two numbers scrawled in a notebook that belonged to terrorism suspect Zacarias Moussaoui could have given the FBI a chance to identify several of the Sept. 11 hijackers before they struck six years ago, according to officials who are familiar with the bureau's massive investigation of the attacks.

The notebook entries recorded the control numbers for two Western Union wire transfers in which suspected Al-Qaida coordinator Ramzi Binalshibh, using an alias, sent Moussaoui $14,000 from Germany in early August 2001, before he went to a Minnesota flight school to learn to fly a Boeing 747 jumbo jet.

A check of Western Union records probably would have uncovered other wires in the preceding days for similar sums of money to Binalshibh -- who'd been turned away at the U.S. border four times because he was a suspected terrorist -- from an Al-Qaida paymaster in Dubai. On one of those receipts, the paymaster listed a phone number in the United Arab Emirates that several of the hijackers had called from Florida.

FBI headquarters, however, rejected Minneapolis FBI field agents' repeated requests for a national security warrant to search Moussaoui's belongings after he was arrested on Aug. 16, 2001. One agent, Harry Samit, was so convinced that Moussaoui was a terrorist that he sent scores of messages to FBI headquarters pressing for a search warrant.

It's not clear whether the FBI would have been able to trace the money and telephone calls fast enough to preempt the Sept. 11 attacks, but the decision to reject the requests for a warrant meant they never had the chance.

Instead, Moussaoui's tattered, blue spiral notebook sat in a sealed bag at an immigration office -- unopened until after four hijacked jets slammed into New York's World Trade Center, the Pentagon and the Pennsylvania countryside, killing 2,972 people.

On Monday, FBI spokesman Rich Kolko said the bureau had "worked diligently on the case" but that "the trail of evidence was complex, and additional information was not available until after the 9/11 events."

Details before the attacks

Officials familiar with the Sept. 11 investigation and with the items in Moussaoui's possession when he was arrested provided McClatchy Newspapers with the most detailed description to date of FBI agents' pre-Sept. 11 path toward the hijackers. The officials declined to be identified because the decision not to seek the warrant has caused friction and embarrassment within the FBI.

After the attacks, FBI agents traced the wire transfers. In addition to the two numbers for the transfers, a succeeding page in Moussaoui's notebook contained the words "Western Union." It also contained a phone number in Hamburg, Germany, that belonged to Ahad Sabet, the stolen identity that Binalshibh used to wire the money.

Investigators following the trail probably would have been quick to discover that Sabet was a U.S. citizen living in Arizona whose passport and credit cards had been stolen in Spain in 1998, raising a red flag about the source of Moussaoui's overseas funding.

Armed with a warrant, the FBI also probably could have obtained a grand jury subpoena for Moussaoui's bank account records in Oklahoma, where he took beginner's flight lessons before he traveled to the Pan Am International Flight Academy in Eagan. A subpoena to the bank after the attack produced the fact that Moussaoui had deposited a Western Union check.

One official said there was a good chance that FBI investigators would have recognized that the two numbers in the notebook resembled Western Union or MoneyGram control numbers, and would have asked those companies to run traces.

Don Rigby, a Western Union official, testified at Moussaoui's trial last year that the company could have responded quickly to an FBI subpoena by providing records of the transfers from Binalshibh -- using the alias Ahad Sabet -- to Moussaoui, and to "Sabet" (Binalshibh) from Mustafa al-Hawsawi, the Sept. 11 paymaster in Dubai, who also was using an alias.

At least one receipt from Al-Hawsawi listed a phone number in the United Arab Emirates. A trace of calls to that number after the attacks revealed 19 calls using four prepaid calling cards purchased by the hijackers, including one that belonged to Marwan al-Shehhi, who had piloted one of the planes that hit the World Trade Center.

Investigation may have led to Atta

A follow-up investigation, including traces of the U.S. calling cards, would have turned up Al-Shehhi's roommate, hijacking ringleader Mohamed Atta, and other hijackers as well as several of their enrollments in flight schools.

Former FBI agent Aaron Zebley, testifying at Moussaoui's trial, said that if Moussaoui had confessed to his role in a suicide hijacking plot, the FBI could have tracked the wire transactions and phone calls quickly before Sept. 11 and identified 11 of the 19 hijackers.