human error. the salahis made it past the secret service check points even though their names weren t on the list. the congresswoman wants to know if anyone else did too. but how did you discover that the salahis had entered? we were advised of it, the following day. and advised by whom, sir? the facebook. so for all we know, there were other people there. reporter: sullivan says preliminary findings are the salahis were the only crashers. was there threat to the president or not a threat to the president? we have countermeasures in place. i m confident to tell you there was no threat to the president. the white house has already changed the security rules. a staffer will be at every check point from now on with a list of the inten des. are we just going to shrug our shoulders and say it was human error? we re going to look at this, find out what the ability was, and we ll take the appropriate action. reporter: three secret service agents who broke p