DEKALB COUNTY, Ga. — A suspicious letter delivered to an office inside the DeKalb County courthouse on Tuesday forced an evacuation and heavy police presence in the Decatur area. 

The letter, which was received in the Clerk of Superior Court’s office, according to authorities, had a note claiming that the envelope also contained anthrax. There was nothing in the envelope except the note. 

DeKalb County Deputy Fire Chief Vera Morrison said those in the office were ordered to shelter in place before the the building was evacuated. 

"What we do know is the letter came from a prisoner or a prison camp," Vera said. 

She added that this is something authorities have seen before. 

According to protocol, the note was tested and found to be "harmless," police said. The Federal Bureau of Investigation, Georgia Bureau of Investigation and homeland security are investigating the scene as well. 

Several roads were closed in the downtown Decatur area during the investigation, police confirmed, but they were later reopened.