Threatening letters containing a suspicious white powder sent to more than 30 banks across the US were being investigated by the FBI today.
Police were treating it as a first, if extreme, public backlash over the nation’s financial crisis.
Initial tests on the powder proved negative for toxins and it appeared the powder was harmless calcium.
Additional tests were being run on the letters as the FBI zeroed in on possible suspects near Amarillo, Texas, where the letters were postmarked.
“Most of these letters contain a powder substance with a threatening communication,” the FBI said.
“Even sending a hoax letter is a serious crime.”.
A spokesman said the letters were sent to Chase bank branches in or near Atlanta, Chicago, Columbus, Ohio, Dallas, Denver, Newark, New York, Oklahoma and Washington. They all appeared to be from the same source and began arriving on Monday.
The FBI would not release the text of the letters but said the threat was “based on past actions of the bank” and that they implied that the opener was going to die.
The letters were sent against a backdrop of eroding trust in US financial institutions.
The crisis has left home foreclosures at record highs, has shrivelled savings and rocketed unemployment.