James Jay Lee -- the gunman who took hostages today at the Discovery Channel headquarters in Maryland -- has died after being shot by police.



According to police, Lee unsuccessfully spoke with several negotiators during the standoff.

Cops say tactical officers managed to get close to Lee ... and saw him point a handgun at one of the hostages. That's when officers decided to open fire  ... killing Lee.

Law enforcement claims Lee made several demands that "mirrored" the demands he had made on his radical website.

Story developing...

Cops have just announced ... they have shot James Jay Lee -- the man who took hostages at the Discovery Channel building in Maryland earlier today.



All of the hostages are safe and accounted for.

So far, cops say they have no information on the condition of the suspect.

Cops say one of the devices strapped to Lee exploded during the confrontation.

Lee is currently in police custody.

Cops say the building has not been deemed safe yet because there may be explosives in some of Lee's backpacks.

Story developing ...

A man wielding a gun and possibly carrying an explosive device is holed up at the Discovery Channel headquarters in Silver Spring, MD -- and now he's been identified by the network as radical environmentalist -- James Jay Lee -- who has had a grudge against Discovery for years.



Lee recently published a manifesto listing his demands to the Discovery Channel ... including the immediate stop to "encouraging the birth of any more parasitic human infants."  Lee also lashes out about Discovery Channel programs promoting war and technology.

Law enforcement tells TMZ ... Lee was arrested during a protest in 2008 for disorderly conduct outside the Discovery Channel headquarters.

After the gunman entered the building earlier today ... an employee told a local TV station, "We heard, pop, pop, pop, pop pop."

A day care center in the building -- with 100 kids -- has been evacuated.

The SWAT team is on scene. The drama has been unfolding since around 1 PM ET.

UPDATE: Lee is reportedly demanding to speak with Discovery Channel executives.

Law enforcement officials confirm that Lee is still holding a "small number" of hostages. Officers have not confirmed the exact number of people being held.

Cops also say ... they believe Lee has a number of metallic containers strapped to himself that could be explosive devices.

UPDATE 12:30 PM PST: A source on the scene tells TMZ the SWAT team has just entered the building.

UPDATE 12:55 PM PST: The local police chief is set to address the media in the next few minutes.

UPDATE 1:03 PM PST: Cops say they have not confirmed any injuries so far.

Story developing...

James Jay Lee -- the gunman currently holed up with hostages at Discovery Channel headquarters -- was ordered to a mental institution after a 2008 environmental protest ... TMZ has learned.


Lee was arrested for disorderly conduct during his protest outside Discovery headquarters in Maryland two years ago -- after allegedly trying to draw a crowd by throwing money all over the sidewalk.

Lee was found guilty of disorderly conduct -- and the court ordered him to serve time in a mental institution.

But according to sources, Lee never stepped inside a hospital -- we're told he was released after 14 days in a local jail ... and got off with 2 years supervised probation.

We took your questions on everything today -- including the hostage situation at the Discovery Channel headquarters, Tiger Woods' $54 million mortgage, and Michael Lohan moving to L.A. to be near Lindsay.


Plus: Heidi makes Spencer pull out on sex tape deal.