About 40% of illegal aliens in the US overstay their visas.
Reuters reports here:
The FBI found nothing to suggest [Tamerlan Tsarnaev] was an active threat, but all the same placed his name on the "Terrorist Identities Datamart Environment" list. The FBI has not said what it did find about Tsarnaev.
But the database, which holds more than half a million names, is only a repository of information on people who U.S. authorities see as known, suspected or potential terrorists from around the world.
Because of its huge size, U.S. investigators do not routinely monitor everyone registered there, said U.S. officials familiar with the database.
As of 2008, TIDE contained more than 540,000 names, although they represented about 450,000 actual people, because some of the entries are aliases or different name spellings for the same person. Fewer than 5 percent of the TIDE entries were U.S. citizens or legal residents, according to a description of the database on the NCTC website.
