Federal authorities posted a $100,000 reward for help in finding who sent identical letters containing what turned out to be a harmless white powder to banking offices across the country. All 50 letters, which were sent between Oct. 17 and 18, were postmarked Amarillo, Texas.

Today the FBI today released the text of the letters on its Web site: "STEAL TENS OF THOUSANDS OF PEOPLE'S MONEY AND NOT EXPECT REPERCUSSIONS. IT'S PAYBACK TIME. WHAT YOU JUST BREATHED IN WILL KILL YOU WITHIN 10 DAYS. THANK (Redacted) AND THE FDIC FOR YOUR DEMISE."

Among the places the letters were sent:

-- Nine Chase branches in Phoenix, Mesa and Gilbert, Ariz.

-- Eight Chase branches in an around Oklahoma City;

-- Eight Chase branches in Jamesburg, Monroe, North Brunswick, South Brunswick, Howell, Lakewood, Toms River and Watchung, N.J.;

-- Chase branches in Lakewood, Colo., Elgin, Ill., Columbus, Ohio;

-- Federal Deposit Insurance Corp. offices in Arlington, Va., and Dallas;

-- A branch of the Federal Home Loan Office in Atlanta;

-- Office of Thrift Supervision offices, including one in Irving, Tex.

One letter, addressed to Jamie Dimon, chief executive of JP Morgan Chase in New York, threatened a series of attacks "ending in an Oklahoma City-like bombing," ABC News reported.

"People who have mailed these kinds of hoax letters in the past have received some serious jail time," said FBI Special Agent Richard Kolko. "This investigation will continue until those responsible are arrested, and we appreciate the public's support by providing information."