A group of scientists is casting doubt on an FBI investigation, saying the man they accused of mailing anthrax may have had help—or may have been the wrong man entirely. In an article in The Journal of Bioterrorism & Biodefense, they point to the presence of tin in the samples, which indicates the poison was more sophisticated than the FBI claimed. The Government Accountability Office, which is conducting its own review of the investigation, said the scientists' paper raised important questions that should be addressed.
