SILVER SPRING, Md. – A man who railed against the Discovery Channel 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.

A law enforcement official speaking on condition of anonymity because the investigation was ongoing said authorities had identified James J. Lee as the likely suspect.

A lengthy posting that could be seen Wednesday on a website registered to Lee said Discovery and its affiliates should stop “encouraging the birth of any more parasitic human infants,” a possible reference to shows like “Kate Plus 8” and “19 Kids and Counting.” Instead, he said, the network should air “programs encouraging human sterilization and infertility.”

The hostages — two Discovery Communications employees and a security guard — were unhurt after the four-hour standoff.

An explosive device on the gunman’s body detonated when police shot him, Manger said.

Lee was convicted of disorderly conduct for a protest he organized outside Discovery’s offices in February 2008. According to court records, he paid homeless people to carry signs and set off a scramble for money when he threw fistfuls of cash into the air, calling it “just trash.”

On Wednesday, Adam Dolan, a sales director in Discovery’s education division, said that when he got to the bottom floor he saw shattered glass near the company’s day-care center and suspected it was broken to get the children out.

He later got an e-mail saying the children were safe and had been taken to a McDonald’s.

Dolan said the company has unarmed security guards who won’t let anyone into the building without a badge.

David Leavy, a Discovery vice president, hopes and expects to be open Thursday. “The priority is going to be nurturing and responding to employee needs over the coming days as this is a scary event,” he said.

Discovery officials are familiar with the suspect and his past protest at the building, Leavy said.

At Lee’s trial, The Gazette of Montgomery County reported, 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.”

Quinn told The Associated Press that he found out about the standoff in Maryland from the media. He said he had never heard of Lee and was stunned that Lee’s manifesto advocated things like human sterilization and an end to farming.

“He wants to get more exposure … and he thinks that he can get it … by occupying Discovery,” Quinn said.

He added that if he could talk to Lee, he would tell him “he’s giving a bad name to the ideas that he’s trying to espouse.”