know right now and are we confident that this individual is acting alone, that he has no help? >> reporter: that would appear to be the case, chuck. number one, he wasn't stopped by police. he stopped by driving up on the sidewalk of the library of congress. apparently trying to attract attention, knowing he would get a law enforcement response. secondly, he claims to have a bomb but authorities have not seen anything that looks like a bomb, so they don't know. it is entirely based on his claim he has explosive materials. they have to take it as though it is the real thing, that's why you're seeing an understandably massive response. number three, important to point out as the police chief said, he did not claim he had a detonator in his hand. he said he had a bomb. the policeman that came up to the vehicle thought what was in the man's hand could have been a detonator.