Just as a word of warning:
Having co-gm'ed the IAP mystery mafia game, I believe it was a largely failed experiment. My overall impression was that players were dissatisfied with the structure of the game. The game was basically chaos where nobody knew anything. And I did not want to start a mystery-mafia precedent.
With that said, I think it's possible to do a much better job than we did (though we did put in a lot of effort) and I'd be happy to give you some advice on pitfalls to avoid. I think it is fully possible for mystery-mafia to be a good, fun game, but it will take a lot of design and planning. Just know what you're getting into

Though a short summer game is certainly less of a risk. I for one, would definitely play!