Authorities said nearly 50 letters in all, some filled with white powder, have been sent to Chase Bank branches and federal regulatory offices in 11 cities: Atlanta, Chicago, Columbus, Ohio, Dallas, Denver, Newark, N.J., New York City, Okalhoma City, Phoenix, San Francisco and Washington.
So far, the letters have tested negative for poisonous or otherwise dangerous toxins, FBI spokesman Richard Kolko said in Washington.
An FBI spokesman in Oklahoma, where eight letters turned up, said local preliminary assessments showed the powder was harmless calcium.
The letters first began surfacing Monday, forcing some bank branches to close. No injuries were reported, but some Chase employees, including a pregnant woman, were examined as a precaution. Chase branches around the country "are on alert," said JPMorgan Chase spokesman Greg Hassell.
Authorities said the letters appear to be from the same source, and were focusing on possible suspects near Amarillo, Texas, where the envelopes were postmarked.
The incident was being investigated as a first, if extreme, public backlash over the nation's financial crisis.
from the Trib