A local dive shop owner says FBI agents are wasting their time scouring Keys dive shops for information about suspicious people who took scuba classes. On May 23, the FBI released a warning that some terrorists had been seeking "an offensive scuba diver capability." Concerned that future terrorist attacks might come by sea, the bureau apparently is compiling a database of all the country's certified scuba divers. "Why spin your wheels interviewing the dive shops when they should be going right to PADI?" asked Capt. Bill Grosscup, owner of Captain's Corner on Greene Street. The Professional Association of Diving Instructors,...