Nearly a decade after the 9/11 terrorist attacks, counterterrorism officials said in December 2010 that they had made it easier to add individuals’ names to the terrorist watch list. The second iteration of the Terrorist Identities Datamart Environment was scheduled to be launched in January — the first version went live in 2005 — and new criteria says that a credible, single-source tip can lead to a name being added to the watch list. Approximately 440,000 people are on the list, which is a 5 percent increase over 2009, The Washington Post reported.

Although a majority of the names on the watch list are of non-U.S. citizens, law enforcement and

intelligence agencies are ramping up efforts to thwart an increasing issue: terrorist threats from U.S. citizens. The issue is explored by Emergency Management magazine's The Changing Face of Terror in the U.S.

This view of the smoldering World Trade Center rumble is on Oct. 28, 2001 -- the day of the memorial service at the World Trade Center site.

Photo courtesy by Andrea Booher/FEMA