IN MAY of 2004, the FBI issued an unprecedented apology to Brandon Mayfield, the Portland, Oregon lawyer who was tied to the Madrid train bombings via an erroneous fingerprint identification. (1) The print in question had been positively identified as Mayfield's by three highly qualified FBI examiners and confirmed by Mayfield's own expert. Yet it was ultimately shown to belong to a far more plausible suspect, an Algerian named Ouhnane Daoud, who was linked to the bombings through other evidence. (2) Especially perplexing to the casual observer was the fact that Mr. Mayfield was arrested even though the fingerprint match had been disputed by police in Spain. An even greater ...