On a cold winter night last January, on the outskirts of Milan, Italian anti-terrorist police intercepted a frantic call between two suspected Osama Bin Laden operatives. "They have arrested our brothers ... half of the group," the caller said. "They have found the arms warehouse in Germany." That call, monitored in a cell phone wiretap, and subsequent other intercepts led to the arrest three months later of Essid Sami Ben Khemais, a 33-year-old Tunisian, and five others in Italy on charges of conspiracy, trafficking in arms and explosives, and using false documents.