WASHINGTON - At least 30 letters containing suspicious powder have been mailed to Chase banks in nine cities but so far appear to be harmless, authorities said Tuesday.
The FBI said it was investigating "a series of letters sent to banks around the country."
"These threat letters contain a powder substance," the FBI said in a statement. "At this point, field tests on the powder have been negative. Additional testing will be completed. Even sending a hoax letter is a serious crime."
FBI: Powder-laced letters sent to banks - Crime & courts - MSNBC.com