Very nice idea,
it's a bit hard to get into if you skip reading the description of the game but I like it, I wasn't sure if the chat was actually useful that much - I mean the free typing, except for fun, I imagine you just collect evidence and you wouldn't even need to speak with the person much? why present evidence if you can just detain the person
otherwise maybe some "pre-made" sample questions could be useful to actually know what you should be asking maybe, but I may missed something
not sure if I can think of much else