James Lee, a suspected environmental extremist who was also wearing what appeared to be metallic canister devices, died after he was taken into custody. The three hostages are safe, according to reports.
A police spokesman says Lee entered the network's offices in Silver Spring and pulled out a gun. Authorities had been negotiating with him after he made demands and expressed concerns with the Discovery Corporation, according to Capt. Paul Starks.
Bomb technicians from the FBI and ATF responded to the scene and almost all of the 1,900 employees inside were evacuated but "a few" remained on the upper floors, Montgomery County Police Chief J. Thomas Manger told reporters.
Lee was previously arrested in 2008 for disorderly conduct after throwing money in the air during a rally outside the Discovery building, Maryland's Gazette reported. According to the paper, he spent almost two weeks in jail following the arrest and was evaluated by state psychiatrists.
A San Diego, Calif., native, Lee has been linked to an angry manifesto that was posted on a Web site that lists 11 demands and accuses Discovery's programming of "causing more harm than good."
Among his demands: "Saving what's left of the non-human Wildlife by decreasing the Human population" and taking shows that encourage "the birth of any more parasitic human infants" off the air.