"The man would not say what company he was with or produce identification."
That part says it all. I'd call the local police first, then the FBI. It seems more likely that he is a would-be child molester, or burglar, than terrorist, that's why the locals first. But I'd definately call them both. I also wouldn't hesitate to confront the guy with a group of people. Any legit door-to-door salesman would not hesitate to produce ID.
This is what I think...thank you very much everyone.
If I had evidence that a terrorist act in Waco, TX resulted in the murder of about 80 people, including children and infants, do you think I should contact the FBI with this information? I also have some information that a mother nursing her baby in Ruby Ridge, ID, may have been murdered in cold blood. Is this the sort of thing the FBI would be interested in?