>> she got a little tempered. whew, got a little heated. but first, new details about the security scare which started last week. fbi agents have questioned and cleared some 300 people in connection with the possible plot. >> and police across the country were on high alert as the nation marked this 9/11 anniversary. abc's chief investigative correspondent brian ross has the latest details. >> reporter: u.s. authorities tell abc news there is still no hard evidence that the vehicle bomb plot threat is real. the fbi has now interviewed and cleared some 300 people who were on flights that might have matched the description according to a cia informant of three men coming into the country. even so, security remains heavy and will remain heavy through monday in both new york and washington. with the security has come security jitters. on sunday, an americananirlines flight from los angeles into new york, american flight 34, had f-16 fighter jets escort it for the last 100 miles into the airport.