Quote:

 

Robert S. Mueller, III, Director, FBI, Commonwealth Club of California

The hijackers also left no paper trail. In our investigation, we have not uncovered a single piece of paper either here in the U.S. or in the treasure trove of information that has turned up in Afghanistan and elsewhere that mentioned any aspect of the September 11th plot. The hijackers had no computers, no laptops, no storage media of any kind. They used hundreds of different pay phones and cell phones, often with prepaid calling cards that are extremely difficult to trace. And they made sure that all the money sent to them to fund their attacks was wired in small amounts to avoid detection.

site: www.fbi.gov page: www.fbi.gov/pressrel/speeches/speech041902.htm