The crime spree spanned across a wide swath of Southern California, prompting several police agencies, including the FBI and US Marshall Service, to form a joint investigative task force.

WSJ: L.A. Authorities Announce $1 Million Reward for Ex-Officer Christopher Dorner

An employee of the Defense Department's Criminal Investigative Services, assigned to the Joint Terrorism Task Force, ultimately decided to drop the investigation after reviewing the intercepted communications and Hasan's personnel files.

CNN: STORY HIGHLIGHTS

An employee of the Defense Department's Criminal Investigative Services, assigned to the Joint Terrorism Task Force, ultimately made the decision to drop the investigation after reviewing the intercepted communications and Hasan's personnel files.

CNN: STORY HIGHLIGHTS

And today, Secretary Napolitano and the Attorney General Eric Holder are formalizing a joint task force between the Department of Homeland Security and the Department of Justice that will leverage the investigative capabilities of both agencies to work with Mexico in tracking down the perpetrators.

WHITEHOUSE: Press Briefing