Which is scarier, the noise or the silence? Long after the attacks of Sept. 11, the clangor of terror echoes worldwide. But for U.S. investigators, what they don't hear is almost as frightening as what they do.
Terrorist communications, according to Francis X. Taylor, the State Department's counterterrorism coordinator, have reached levels "probably as high as they were last summer." Attacks continue. In April, a truck bomb--now thought to be the work of Islamic terrorists with links to al-Qaeda, the network headed by Osama bin Laden--crashed into a synagogue in Djerba, Tunisia, killing 19, including 14 German tourists. On May 8,...