The Waterbury Superior Court was evacuated because of a bomb threat, according to Waterbury police.
The courthouse is located on Grand Street.
State police said the call was made to a local news organization and also included threats against Hartford and New Haven courts.
Lt. Paul Vance, of Connecticut State Police, said investigators swept courthouses and did not find anything.
Criminal charges will be filed against the person found to be responsible for the threats.
The courts have not yet opened for the day, so those courts have not been evacuated.
No further information is available.