I agree a greater variety of clue types would make it more interesting. And then maybe each clue you reveal increases the chances of some failure outcome (e.g.

I agree a greater variety of clue types would make it more interesting. And then maybe each clue you reveal increases the chances of some failure outcome (e.g. murderer escapes, kills again, etc)? That would definitely prompt more caution and strategic thinking before revealing the next clue.