the Democratic Party, one answer is found on the envelopes of those letters.
George Monbiot, more than four years ago:
In December, the Washington Post reported that genetic tests showed that the variety used by the terrorist was a sub-strain cultivated by scientists at the US army's medical research institute for infectious diseases (USAMRIID) at Fort Detrick, Maryland. That finding was publicly confirmed two weeks ago, when the test results were published in the journal Science. New Scientist magazine notes that the anthrax the terrorist used appears to have emerged from Fort Detrick only recently, as the researchers found that samples which have been separated from each other for three years acquire "substantial genetic differences".
...
Last week, I phoned the FBI. Why, I asked, when the evidence was so abundant, did the trail appear to have gone cold? "The investigation is continuing," the spokesman replied. "Has it gone cold because it has led you to a government office?" I asked. He put down the phone.
Had he stayed on the line, I would have asked him about a few other offenses the FBI might wish to consider. The army's development of weaponized anthrax, for example, directly contravenes both the biological weapons convention and domestic law. So does its plan to test live microbes in "aerosol chambers" at the Edgewood Chemical Biological Center, also in Maryland. So does its development of a genetically modified fungus for attacking coca crops in Colombia, and GM bacteria for destroying materials belonging to enemy forces. These, as the research group Project Sunshine has discovered, appear to be just a tiny sample of the illegal offensive biological research programs which the US government has secretly funded. Several prominent scientists have suggested that the FBI's investigation is being pursued with less than the rigor we might have expected because the federal authorities have something to hide.
The FBI has dismissed them as conspiracy theorists. But there is surely a point after which incompetence becomes an insufficient explanation for failure.