A man who railed against the Discovery Channel's environmental programming for years burst into the company's headquarters with at least one explosive device strapped to his body Wednesday and took three people hostage at gunpoint before police shot him to death, officials said.
The hostages -- two Discovery Communications employees and a security officer -- were unhurt after the hourslong standoff.
Montgomery County Police Chief Thomas Manger said tactical officers moved in after officers monitoring James Jay Lee on building security cameras saw him pull out his handgun and point it at one of the hostages.
An explosive device on the gunman's body detonated when police shot him, Manger said. Police were trying to determine whether two boxes and two backpacks the gunman also contained explosives.
Lee, a longtime protester at the building who was sentenced to six months of supervised probation for disorderly conduct in March 2008. Lee was upset about the network's programming.
At the time of his conviction in March 2008, Lee was identified as a 40-year-old man from San Diego, according to MSNBC. At the trial, Lee said he began working to save the planet after being laid off from his job in San Diego.
He said he was inspired by "Ishmael," a novel by environmentalist Daniel Quinn and by former Vice President Al Gore's documentary "An Inconvenient Truth."
According to NBCWashington, Lee has had a home in Washington, D.C. for at least two years.
Lee appears to have posted environmental and population-control demands online, saying humans are ruining the planet and that Discovery should develop programs to sound the alarm.
Discovery Communications Inc. operates U.S. cable and satellite networks including The Discovery Channel, TLC and Animal Planet. Discovery shows include "Cash Cab" and "Man vs. Wild," and TLC airs "American Chopper" and "Kate Plus 8."
David Leavy, Discovery's executive vice president for corporate affairs, said all employees had been accounted for. "We're relieved that it ended without any harm to our employees," he said.