Actions to Aid Probe Appear Now As Cover-UpWASHINGTON -- One night in autumn 2001, as the U.S. reeled from the worst act of bioterrorism in its history, Bruce Ivins was alone in his cluttered Fort Detrick, Md., office, scrubbing phones, walls and furniture. ...... Dr. Ivins, his colleagues said, argued that al Qaeda was responsible. "He was very passionate about this," former boss Jeffrey Adamovicz said. "He was very agitated." In these conversations, Dr. Ivins dwelled at one point on a purported link between Florida victim Robert Stevens, a photographer for American Media, and an apartment rented to 9/11 ringleader...