NBC 4 Reporter Mark Segraves said a Navy Yard spokesman told him that they have located the person who made the original emergency call. That person apparently thought there might have been a gunshot fired. Navy officials have still not determined whether any gunfire took place.
CBS News said that two floors of a building have been cleared with no shooter, weapons or casualties found. A third floor was being searched.
“Nothing found so far,” Metropolitan Police Chief Cathy Lanier told CBS News correspondent Kris Van Cleave.