The FBI said it was trying to determine if there is a connection among telephone bomb threats to facilities in 30 counties of Tennessee on Tuesday and similar recent incidents in other U.S. states.
Courthouses and public facilities in 30 Tennessee counties were temporarily evacuated on Tuesday following a rash of such calls.
Similar threats closed more than a dozen courthouses in Oregon last week and bomb threats were also made in Washington state and Nebraska. All affected facilities in Tennessee had been searched by late on Tuesday.
“There were no devices found,” said Dayla Qualls, spokeswoman for the state Department of Safety and Homeland Security.