By Benjamin Goad - 04/17/13 04:26 PM EDT
The ricin-laced letters sent to Washington leaders this week come a decade after anger over trucking regulations were expressed in similar attacks involving the poison.
In 2003, a letter containing ricin and signed by “Fallen Angel” was discovered at a U.S. Postal facility in Greenville, S.C. The type-written letter demanded the repeal of new “hours of service” rules requiring more rest for truckers that were set to take effect.
A second letter that was addressed to the White House the same week contained similar language and threatened to turn “D.C. into a ghost town.”
The FBI announced a reward of up to $100,000 leading to the conviction of those responsible, but no arrests were made.
The FBI did not immediately respond to a request for comment on whether the new cases are being investigated as potentially linked to the “Fallen Angel” letters.
However, in a statement issued Wednesday afternoon, the FBI said letters sent this week to President Obama and Mississippi Sen. Roger Wicker (R) might not be the last uncovered.
“The investigation into these letters remains ongoing, and more letters may still be received,” an FBI statement said. “There is no indication of a connection to the attack in Boston.”
The new letters follow last week’s arrest of a man who made a bomb threat after demanding to see the president.
Krzystzof Wasik, 44, was reportedly upset over trucking regulations.