John Lennon's Killer Speaks Out

The man who murdered John Lennon 25 years ago says "nothing could have stopped" his twisted quest to track down and assassinate the ex-Beatle.

"I was under total compulsion," killer Mark David Chapman says in a segment to be aired at 8 p.m. EST Friday on "Dateline NBC."

"It was like a train, a runaway train, there was no stopping it."

Chapman fatally shot Lennon on Dec. 8, 1980, as the musician and his wife, Yoko Ono, returned home from a night in a Manhattan recording studio. Chapman's comments came from audiotapes made in 1991-92 and first used as part of a British documentary.

Chapman recalled waiting for Lennon that night, then reacting as he saw a limousine pull up outside the ex-Beatle's home.

"I heard a voice in my head saying, 'Do it, do it,'" Chapman recounted. "And as he passed me I pulled out the gun, aimed at his back and pulled the trigger five times in succession."

Chapman recalled that his desire to kill Lennon began one day in his apartment in Hawaii, where he was sitting on the floor and looking at the Beatles' "Sgt. Pepper's Lonely Hearts Club Band" album. His animosity soon began to consume Chapman.

"There was a successful man who kind of had the world on a chain, so to speak, and there I was, not even a link of that chain, just a person who had no personality," Chapman said. "And something in me just broke."

Chapman, 50, is eligible for parole again next year. Ono has repeatedly argued against Chapman's release, and his bids for freedom were already rejected three times by the state parole board.