Cookies mailed to the U.S. Supreme Court last year contained enough rat poison to kill all nine justices, retired member Sandra Day O'Connor said at a conference last week.

Barbara Joan March, a 60-year-old Connecticut woman, was sentenced last month to 15 years in prison. She sent 14 threatening letters in April 2005 -- each with a baked good or piece of candy laced with rat poison -- to a variety of federal officials: the nine Supreme Court justices; FBI Director Robert Mueller; his deputy; the chief of naval operations; the Air Force chief of staff and the chief of staff of the Army.
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Authorities said March included fake handwritten signatures of the purported senders of the letters whose names and return addresses were typed both in the body of the letter and on the envelopes.

Prosecutors said the purported senders live throughout the United States, and were connected to March in various ways, including being classmates, a former co-worker and a former roommate.