Immigrants with long-expired visas tough to track 

By the time the suspect in an alleged bomb plot against the U.S. Capitol was arrested in a parking lot, wearing what he thought was an explosive-laden suicide vest, he had been living illegally in the United States for 12 years.
http://www.beloitdailynews.com/news/national/immigrants-with-long-expired-visas-tough-to-track/article_21be02f1-a321-5b85-93a4-29e1f4ca7703.html