The gunman who stormed the Discovery Channel's headquarters in Maryland said he hated the network's shows because they promoted population growth.

Police shot and killed 43-year-old James Lee during the standoff on Wednesday. He was armed with a gun and explosives when he took two employees and a security guard hostage. The hostages were not harmed during the incident.

Lee allegedly had issues with the network's shows like "Kate Plus 8," because they promoted population growth.

"Humans are the most destructive, filthy, pollutive creatures around and are wrecking what's left of the planet with their false morals and breeding cultures," Lee wrote on his website.

He also targeted the channel back in 2008 when he staged a Save the Planet Protest.

Police were combing the building looking for more explosives the suspect might have planted.

"We're relieved that it ended without any harm to our employees," said David Leavy, Discovery's executive vice president for corporate affairs.