Updated

The Sept. 11 terrorist attacks were financed with a $500,000 bankroll, a law enforcement source said Saturday as the FBI sent more agents to Germany in the search for masterminds of the plot.

FBI agents tracked the hijackers' bank accounts, their communications and their travel tickets as they followed a trail that could lead to a small group of chief plotters in Europe and the Middle East.

The FBI said it's pursuing more than 100,000 leads as agents narrowed their overseas search. Simultaneously in the U.S., more than 100 investigations were under way into alleged hate crimes against Arab-Americans.

The law enforcement source, speaking only on condition of anonymity, said the half-million dollars is all linked in some way to the plot. The Washington Post reported Saturday the FBI documented numerous large cash withdrawals and a long trail of hotels, rental cars and airplane trips.

The FBI has focused on Usama bin Laden sympathizers in England, Germany and the United Arab Emirates, authorities told The Associated Press. One official said more agents have been sent in recent days to Germany, where a cell of Usama bin Laden's Al Qaeda network was said to be operating in Hamburg.

Time magazine reports in its issue on newsstands Monday that Mohamed Atta, a leader of the hijackers, received wire transfers of cash on Sept. 8 and 9 via a money service in Florida. It said FBI records showed the sender was Mustafah Ahmed, a suspected bin Laden financial operative in the Middle East.

While investigating some 120,000 tips sent to an FBI Internet site and toll-free hotline, laboratory specialists examined more than 200 submissions of evidence from the Pentagon, World Trade Center and western Pennsylvania crash sites of hijacked airliners. More than 106,000 leads have been generated by FBI field offices.

Along with the search for the terrorist plotters, the bureau said it was pursuing those committing alleged hate crimes in the United States.

More than 104 investigations were initiated, involving alleged attacks or threats against Arab-American individuals and institutions.

The FBI, CIA and other U.S. agencies have painstakingly recreated the travels of the 19 hijackers over years through Germany, Afghanistan, Spain and London.

Much of the effort has focused on Germany, where federal authorities on Saturday announced the arrest of three Muslim men suspected of plotting attacks in that country.

The prosecutor's office said it had no evidence linking the men to the Sept. 11 attacks.

"The accused are suspected of plotting violent attacks in Germany while belonging to an organization with a fundamentalist Islamic background," the statement said. It did not give details.

On Friday, British prosecutors identified an Algerian pilot as the primary instructor for four of the 19 airplane hijackers. Lofti Raissi was brought to court in London, where a prosecutor told an extradition hearing he played a crucial role by making sure the hijackers had pilot training.