As Space Bounty Blues is to Cowboy Bebop, this (untitled) game would be to Scooby-Doo. It’s GMless PbtA.
Start with the end in mind: I thought of the final move first.
When you unmask the monster, the gang makes one guess who the culprit is and roll + Clues.
On a 10+, you got it right! Explain how the clues helped lead you to that conclusion.
On a 7-9, you got it (mostly) right. Explain how the clues helped lead you to that conclusion, but be ready to be corrected by the culprit.
On a 6-, you got it WRONG! The culprit will explain step-by-step how they were so close to pulling off their scheme.
Then, the culprit will exclaim “And I would’ve gotten away with it too if wasn’t for you meddling kids!” before being hauled off by law enforcement.
It’s written this way because the gang CAN’T lose. But they can sure be surprised and wrong by how things REALLY were.
(Suggested) scene structure, character roles within the gang, procedures for building the crime scene, random tables for NPCs.