British authorities had at least two of the terrorists who bombed London last July 7 under surveillance in 2004. In an official document examined by NEWSWEEK, a British judge reports that U.K. investigators had pictures and voice recordings of Mohammed Siddique Khan—believed to have been the plot leader—and another suicide bomber, Shahzad Tanweer, meeting several times in February and March 2004 with suspects in an earlier, separate terror plot that U.K. authorities investigated under the code name Operation Crevice. The evidence includes recordings of Khan in a car driven by one Crevice suspect, and evidence showing Khan and Tanweer getting out of a Crevice suspect's car. British media have made only limited references to the evidence because a trial of Crevice suspects is pending, and pretrial publicity is restricted under U.K. law.After July 7, investigators claimed the four suspected suicide bombers were previously unknown to British intel. But as the investigation evolved, authorities quietly made it known that antiterror investigators, presumably working for the secret counterintelligence agency M.I.5, had run across Khan and Tanweer; British authorities decided at the time that they weren't dangerous enough for continuing surveillance. U.S. law-enforcement officials, who asked not to be named because the investigation continues, told NEWSWEEK the name of a third bomber, Germaine Lindsay, also came up tangentially in Crevice. British authorities initially denied they had heard of him before July 7 but now concede they may have. A U.K. official said Tony Blair's government wouldn't comment for legal reasons.