3:15pm: About 24 police cars and multiple FBI present at 1350 Connecticut Ave NW.
3:30pm: Dupont Circle metro station section locked down. Washington Post reports there are no victims nor gunman found.
3:45pm: According to the building security (above Panera), there is a hostage situation. All people nearby are asked to return to their offices.
3:50pm: Circle opened to public traffic, waiting on further news.
My live tweets were featured in the Washington Post News:
DC Police searched the building floor by floor, finding no gunman nor affected victims. Dupont Circle is currently open to public and traffic is back to normal.