Traces of anthrax were found in several letters at the Federal Reserve last week, touching off the same fears that gripped the nation last fall. Federal officials quickly reassured the public that the tests were most likely false positives. But the incident reminded a nation that seven months after the mail attacks that killed five and sickened several others, the FBI seems no closer to finding the source of the letters.

Scientists finally uncovered the genetic fingerprint of the anthrax used in the Florida attack, but the most important questions remain unanswered. Where did the anthrax spores come from? Why did the anthrax become finer and more volatile in each subsequent letter? Why did the attacks suddenly stop?

Anthrax expert Jeanne Guillemin has just returned from a week of interviewing workers at the Brentwood mail facility and staffers in the Hart Senate Office Building. This hour, she shares the latest on the anthrax investigation: what we know; what we don’t; and what is being done to prevent another anthrax attack from terrorizing the United States.

Guests:

Jeanne Guillemin, Professor of Sociology at Boston College, Senior Fellow at MIT Security Studies Program