Plot Twists

By Harriet Barovick, Elizabeth L. Bland, Nadia Mustafa, Jeffrey Ressner and Sora Song

DUST PROBE: The FBI gave the detainee Zacarias Moussaoui a test for the anthrax vaccine. Result: negative. A would-be pilot, he was arrested last August with literature on crop dusters in his possession. He is being held as a material witness in the Sept. 11 case. TOWERING TARGETS: In 1999, Spanish police intercepted a van with more than a ton of explosives. Last week a captured Basque separatist said the target had been Madrid's 48-story Picasso Towers, designed by the World Trade Center architect.