US Capitol Police [press conference]: So far, nothing. We've found nothing concerning, we've got nobody that actually heard shots…as we've gone through the building, no one has said that they've seen anything.

Reporter: Have you made initial contact with anyone who might have made that first 911 call?

Capitol Police: The original caller to MPD, the call just bounces back; they've tried a couple of times, and it comes back to a different location every time…this may have been a bogus call.