During the retrial of suspected Moroccan terrorist Mounir El Mostassadeq, an FBI agent testified that the organization of the Sept. 11 attacks took place primarily in Hamburg. Special agent Matthew Walsh said the idea may have come from Afghanistan, but the how, who and when was developed in Germany. During his testimony, Walsh recapitulated how "hellish" the minutes on the airplanes must have been before they hit their targets. He did this at the urging of the son of one of the passengers on the plane hijacked by Mohamed Atta and then flown into the World Trade Center. In February 2003, Motassadeq was convicted of involvement in the attacks and sentenced to 15 years in prison. He then won an appeal after a higher court ruled that potentially important evidence had not been made available in the first trial.