optimistichttp://www.inopressa.ru/article/07jul2016/time/fbi.html
Оригинал:
Both the FBI and CIA placed Tsarnaev on watchlists, and though they “pinged” to alert authorities when he bought airline tickets, traveled to, and returned from Russia, he was not re-investigated or screened as requested at the airport because there were too many other watchlisted people of higher priority traveling that day.
http://time.com/4389947/fbi-national-security/