Conversation so far:
what was the development of the movie chapter 27?
Chapter 27 is based on the text Let Me Take You Down: Inside the Mind of Mark David Chapman, a book of Chapman's recollections of his act of violence.
what else was the movie Chapter 27inspired by besides a book?
The murder of John Lennon by Mark David Chapman.
what was John Lennon's biggest accomplishment?
He gained worldwide fame as the founder, co-lead vocalist, and rhythm guitarist of the Beatles.
Are there any other interesting aspects about the Chapter 27 movie article?
Chapman's motives were fabricated from pure delusion, fueled by an obsession with the fictional character Holden Caulfield and his similar misadventures in J.D. Salinger's The Catcher in the Rye.

Question: why is he incarcerated?
Self-contained rewrite: why is Mark Chapman incarcerated?