The F.B.I. missed at least five chances in the months before Sept. 11, 2001, to find two hijackers as they prepared for the attacks and settled in San Diego, the Justice Department inspector general said in a report made public on Thursday after being kept secret for a year. Investigators were stymied by bureaucratic obstacles, communication breakdowns and a lack of urgency, the report said. The blistering findings mirror those of the independent Sept. 11 commission last summer and a joint Congressional inquiry in 2002 but they also provide significant new details about the many bureaucratic breakdowns that plagued the Federal Bureau of Investigation before the attacks and are likely to fuel questions about the bureau’s efforts to remake itself. Full Story