Maryland State Police are investigating the mailing of a letter with baking powder inside from Virginia to Annapolis.
Police say an employee at the Maryland District Court Administration building opened a letter with white powder inside about 9 a.m. Wednesday. The letter was opened in a room for sorting mail for the District Court.
The building was evacuated while troopers, hazmat teams and emergency crews examined the scene and decontaminated four people in the office where the letter was sent.
Virginia police are assisting in the investigation because the letter was mailed from Richmond.
Employees were let back in the building at noon and no one was injured.