Conversation so far:
When did the film begin development?
CANNOTANSWER.
Why did they decide to do a film about this?
to understand "how someone could be inspired to kill anyone as a result of being exposed to this kind of beautiful art.
Who said that?
Schaefer.
What else did Schaefer say?
It really bothered me, because Lennon and Salinger have always made me feel so much better, and so much less alone..
Are there any other interesting aspects about this article?
The real Mark David Chapman is currently incarcerated at Wende Correctional Facility, on a guilty plea.

Question: How did they get the details to make a movie?
Self-contained rewrite: How did Chapman get the details to make a movie?