1.   Koplan explained that federal health officials were working under the assumption that anthrax exposure could only take place with an opened letter rather than just handling a tainted letter.

2.   American authorities hoped a newly opened letter to U.S. Sen. Patrick Leahy would provide crucial clues to help solve the anthrax-by-mail attacks.

3.   Meanwhile, authorities hoped a newly opened letter to U.S. Sen. Patrick Leahy would provide crucial clues to help solve the anthrax-by-mail attacks.

4.   Meanwhile, a newly opened letter to Sen. Patrick Leahy contained suspected anthrax and handwriting that appear identical to an earlier letter to Daschle, the FBI disclosed.