Discovery Communications Headquarters Invaded By Gunman

UPDATE (6PM): According to NBC's Washington, D.C. affiliate, the police have confirmed the suspect is dead.
UPDATE (5PM): TBD.com reports that police shot the suspect. His condition is unknown.
The Discovery Communications headquarters building in Silver Spring, Md. has been shut down after a gunman possibly bearing explosives took hostages, CNN reports.

Montgomery County Cpl. Dan Friz told ABC news station WJLA that the suspect was carrying what appeared to be an "explosive device." A SWAT team surrounded the 10-story building and police chief Tom Manager said negotiations with the gunman are ongoing.

A MySpace profile reportedly belonging to the gunman -- who AOL News says has been identified as James Jay Lee of Silver Spring -- lists "The Discovery channel" as one of his television interests. Lee's most recent status update is from January 2008, and reads "Lee says: It's time for REVOLUTION!!"

The ABC affiliate's website, TBD.com, reported that Lee had a history with Discovery, including an arrest for protesting against the network in 2008.

According to a the WUSA9 news station's Twitter, Lee allegedly posted an online manifesto (also linked to from the MySpace page) demanding that Discovery Communications channels -- including Discovery, TLC, Animal Planet, the Science Channel and more -- air certain types of programs. The document details how "The Discovery Channel MUST broadcast to the world their commitment to save the planet" and urges the company "to do the following IMMEDIATELY."