Malaysia Airlines Flight 370: Efforts to find missing Malaysia Airlines Flight MH370 have begun to focus on someone in the cockpit – one of the pilots or an intruder – as the search expands to 35,000 square miles.
Federal officials in Chicago and Brooklyn have already said they will seek the extradition of drug kingpin Joaquín 'El Chapo' Guzmán. The Obama administration hasn't taken an official position on the matter.
Security concerns for the Olympics in Sochi are on the rise among US officials, as video threats surface and the Russians hunt for suspected 'black widow' suicide bombers. US military is forced into 'contingency planning.'
Janet Napolitano guided DHS through challenging times marked by debates over border security and immigration, airport security policies that critics say were too intrusive, and scrutiny of the federal response to natural disasters.
Joe Lieberman testified in Congress that better coordination between federal and local law enforcement or a tip to police from someone who knew of Tamerlan Tsarnaev's views could have prevented the bombing.
Student visa snafu involving a Kazakh friend of Dzhokhar Tsarnaev, the Boston bombing suspect, prompts US to beef up security checks. Will the episode undermine chances for comprehensive immigration reform?
Boston bombing suspect Tamerlan Tsarnaev remains the focus of investigation in both Russia and the US, as authorities seek to learn how he became radicalized. Here are four other developments in the case.