WASHINGTON (AP) - Ten days before Timothy McVeigh was executed, lawyers for FBI lab employees sent an urgent letter to the attention of Attorney General John Ashcroft alleging that a key prosecution witness in the Oklahoma City bombing trial might have given false testimony about forensic evidence. The allegations involving Steven Burmeister, now the FBI lab's chief of scientific analysis, were never turned over to McVeigh or the trial court, though they surfaced as the judge was considering whether to delay his execution because the government withheld evidence. The letter, however, was recently turned over to bombing conspirator Terry Nichols...