Scouring the anthrax-laced mail that took five lives and terrorized the East Coast in 2001, laboratory scientists discovered a unique contaminant — a tiny scientific fingerprint that they hoped would help unmask the killer.
One senior FBI official wrote in March 2007, in a recently declassified memo, that the potential clue "may be the most resolving signature found in the evidence to date." Yet once FBI agents concluded that the likely culprit was Bruce Ivins — a mentally troubled, but widely regarded Army microbiologist — they stopped looking for the contaminant, after testing only a few work spaces of the scores of researchers using the anthrax strain found in the letters.
They quit searching, despite finding no traces of the substance in hundreds of environmental samples from Ivins' lab, office, car and home.
It's been two and a half years since Ivins committed suicide in the face of prosecutors' threats to charge him with five murders, each carrying a potential death sentence. It's been more than a year since the Justice Department, despite lacking hard proof, formally declared that Ivins "perpetrated the anthrax letter attacks."
But the FBI's decision not to fully test for the distinct bacterial contaminant, pieced together by McClatchy in interviews with scientists, federal law enforcement officials and in a review of recently declassified bureau records, could reignite the debate over whether its agents found the real killer.
The Justice Department closed the eight-year investigation, said to cost as much as $100 million. However, none of the circumstantial evidence it found showed that Ivins prepared the deadly powder, scrawled "Death to America" in a seeming mimic of al Qaida, or twice sneaked away on six and a half hour roundtrip drives to drop them in a Princeton, N.J., mailbox.
If the FBI got the right man, then there is no consequence to its decision to stop hunting for bacillus subtilis, a harmless bacterial contaminant that resembles anthrax. But if Ivins was innocent, then the killer is at large, and the bureau may have missed a big opportunity.
Some scientists and ex-colleagues of Ivins, who spent 27 years studying anthrax at the U.S. Army Medical Research Institute of Infectious Diseases at Fort Detrick, Md., remain convinced of his innocence and believe the FBI erred in limiting the testing.