forces who want to check in and out of it. so this is a very complex but in today's age a very standard response at the moment when they see these types of situations unfold. carol. >> let's go to our justice correspondent evan perez. any more word from the fbi what's going on at the scene? >> no, they're trying to figure out the lay of the land and get their folks in there. we know there are people inside the building where the shooting took place who have been able to move to other buildings but the problem is as brar bra mentioned and the navy said on their twitter feed, there are about 3,000 people who work in this place. it's a very large complex, from the street, from m street you don't quite see how big this complex is. there's several blocks before you get to the river so there are people who are now sheltering in place in other