however, messing with the train is a federal offense. and that's why the fbi's called in. and the investigation with the faa, if there's anything that looks criminal at all, we immediately notify the fbi, and they may even take over the investigation, depending on the severity. >> do you expect that to happen, tom? >> well, not at this point. i think right now, they just work very closely with the ntsb and the forensics experts from both agencies work all the time together, as david mentioned. not only in airline crashes but this type of thing. you even have road crashes where the ntsb might investigate serious traffic accidents. but could have been the result of somebody throwing a brick off a bridge hitting the windshield of a truck and it strikes other vehicles and causes massive accidents. any type of sabotage that is criminal, the fbi would have it. and both agencies work closely