If you specify a situation that does not resemble a RPG, but rather an incomplete novel, what do you expect it to reveal about RPGing?Like, let me give you an example. Duke Black is slain at a masquerade ball, which is locked down by the police, and the party of detectives (who were invited on a lark by a noble friend of theirs), and the murderer is almost surely still on the premises. The Duke's body was found stabbed. His masquerade mask is missing, and the knife is an ordinary dinner knife, held with a napkin so it has no fingerprints.
The party finds the following clues:
1. The knife actually penetrated the Duke's sternum, which would require quite a lot of force, so only a very strong person could have stabbed him that way.
2. The mask was found in Countess Green's room.
3. The Duke's son Adam, now the new Duke, had crippling gambling debts, but he can pay them off now.
4. The knife was taken from the table where Countess Green, Adam Black, the Duke's old friend Lord Grey, and his physician, Dr. Crimson.
These clues certainly put suspicion off of Lady Black, the Duke's elderly widow, and his butler Timothy Trevelyan...if they are true clues, not false ones. How can the players know? It's unlikely all of them are true clues. E.g. if Countess Green killed him (implied by finding the mask in her room) then the Adam's debts are a red herring. If Adam killed his father, then the mask in the Countess' room is an effort to throw people off Adam's scent.
How can anyone solve this? There isn't an answer, so the clues are neither true nor false, they just are...pieces of evidence that are known. It can't be solved unless and until something is established which either (a) specifies which suspect(s) actually did the dirty deed, or (b) specifies all but one of the potential suspects who couldn't have killed the Duke. But in the moment that last piece is put in place which established who did it...the players didn't solve it. Something--a single player, a collective player effort, an effort of all the participants GM included, a roll, a card, whatever--established the guilt. It wasn't the evidence that led them to that conclusion; it was the procedures, whatever those procedures might be, which made it so someone was and always was the murderer, even though nobody could have known that prior to that moment, even in principle.
For a start, everything that you describe is about the fiction. Nothing you have said describes any process of RPG play.