The existence of the silicon-tin chemical signature offered investigators the possibility of tracing purchases of the more than 100 such chemical products available before the attacks, which might have produced hard evidence against Ivins or led the agency to the real culprit.
But the FBI lab reports released in late February give no hint that bureau agents tried to find the buyers of additives such as tin-catalyzed silicone polymers.
The apparent failure of the FBI to pursue this avenue of investigation raises the ominous possibility that the killer is still on the loose.
A McClatchy analysis of the records also shows that other key scientific questions were left unresolved and conflicting data wasn't sorted out when the FBI declared Ivins the killer shortly after his July 29, 2008, suicide.
Thursday, May 19, 2011
McClatchy's Greg Gordon has written another excellent piece on the anthrax letters. The focus this time is on the silicon and tin added to the spore prep, and how the FBI resolutely failed to investigate them as a means of solving the case:
Posted by Meryl Nass, M.D. at 11:46 PM