SILVER SPRING, Md., Sept. 2 (UPI) -- The brother of the gunman shot dead by police at Discovery Channel headquarters in Maryland said Thursday he believes James J. Lee was seeking death.

"It was definitely out of character," Aaron Lee told ABC News. "I thought it was insanity. I was sad to know that he was shot and killed, but that's what he probably wanted."

Lee, armed with a gun and explosives, entered the building in Silver Spring early Wednesday afternoon and took three hostages. He was killed after a four-hour siege.

Montgomery County Police Chief J. Thomas Manger said deadly force was used because the hostages, all Discovery Channel employees, appeared to be at risk. He said members of a SWAT team heard a popping sound that might have been Lee detonating a bomb or shooting.

"Any time that police officers use deadly force, it's to save a life. ... In this situation the hostages -- who were tremendously courageous throughout this incident -- were in grave danger," Manger said on "Good Morning America."

Lee, who posted long environmental rants on the Internet, had an obsession with the Discovery Channel.