DENVER, Oct. 21 (UPI) -- Chase banks in eight states and the District of Columbia received menacing letters containing white powder this week, federal authorities said Tuesday.
At least 30 letters were received Monday and Tuesday at Chase branches or credit-card facilities in Colorado, Georgia, New York, New Jersey, Texas, Oklahoma, Ohio, Illinois and the District of Columbia, The Denver Post reported. Ten of the threats went to banks in the Denver metropolitan area, the newspaper said.
"At this point, field tests on the powder have been negative. Additional testing will be completed," said Washington FBI Special Agent Richard Kolko.
The letters prompted the evacuation of some banks Monday.
Postal workers in Denver were working with the FBI to determine the origin of the letters, said Jojan Henderson, a U.S. Postal Inspection Service spokeswoman in Denver.
Gary Johnson, spokesman for the FBI in Oklahoma City, said threatening letters received by banks in Oklahoma "basically indicated that the person who opened the letter was going to die." Johnson also said the writer indicated the letters were in response to "an action the bank may have taken."
Kolko pointed out that sending hoax letters is "a serious crime."
"The FBI and postal inspectors are responding to each of these incidents," said Kolko. "It is a tremendous drain on resources."
He said between January 2007 and August 2008, there were 900 such incidents across the United States, with many of them solved by the FBI.