system
Given the following post, respond as if you're commenting on Reddit:
human
[Saw] How did John find out about all these peoples lives.

How does he know that someone cheats on someone with their best friend or that they are a junkie?
gpt
He poses as a sick homeless man when out in the world. Nobody "sees" him and he overhears all sorts of things and has contacts everywhere. Also, given the intricacy of his traps and safehouses its not unreasonable that he can set up surveillance to spy on potential marks and learn their secrets.