I think lying was exactly why he was fired. The man has been in this country for 35 years and been a successful senior TVA manager for many years. Prior to this I can't see any reason or event that would have triggered his being put on a watch list.
Granted what he did was wrong and there could be more that develops but, having worked for him the only Masoud I knew was an extremely smart man. Unfortunate he had to go, but everyone in the nuclear industry knows a lack of trustworthiness" is taken very seriously, as it should be.