A simultaneous bomb threat and anthrax scare forced the evacuation of the state courthouse on Elm Street Thursday afternoon.

Shortly before noon, employees in the clerk’s office received two separate phone calls. The first caller said there was anthrax somewhere in the building, and the second claimed “a bomb with wires in it is somewhere in the courthouse,” said Vincent Landisio, a New Haven Fire Department battalion chief.

After the calls came in, court officials activated the fire alarms, and state marshals helped escort everyone onto the sidewalk and safely away from the building, Landisio said. Prisoners appearing in court that day were taken into the basement lockup facility from which they exited the rear of the courthouse.

Fire department workers then searched the building floor by floor and found no evidence of anthrax powder or explosive devices, Landisio said.

The courthouse reopened shortly after 2 p.m.

Court Clerk Louis Fagnani Jr. said that nearly everyone remained calm during the evacuation.

Fagnani said officials activated the fire alarm because the court building does not have a public address system. He added that many people may not have taken the evacuation seriously if they thought it was a result of a false alarm rather than a potentially serious situation.

“Most people seemed to think it was a joke,” Fagnani said.

He added that there are no plans to install a public address system in the courthouse anytime soon.

“The fire alarms did what they needed to do and got everybody out of there safely,” he said.

Landisio said firefighters normally do not perform thorough searches in response to such calls. Fire Department personnel are usually called on to search for a previously identified dangerous device, in this case a vessel holding anthrax powder or housing explosives.

“The calls didn’t specify any type of container, so we had to search the entire place to make sure it was safe for people and other investigators to go back in,” Landisio said.

State and local police, who also responded to the threat, said the investigation had been turned over to the FBI’s New Haven office.

FBI officials were unavailable for comment Thursday evening.