I don't know if you've played it before or if it has other names but it's this really cool game we used to play at gatherings.
Ok you have a deck of cards and everyone is dealt a card - Count out the number of players (don't count the narrator and only have that amount of cards making sure that 2 of them - or more if there's ALOT of people are Jacks/Jokers for the Mafia and that at least on is a King/Ace as the detective --- just not the number cards. Then deal the cards to everyone but one.
Everyone looks at their card then closes their eyes.
The Narrator starts the story and the more creative the Narrator the more fun and interesting the game is "Towns people go to sleep and while they're asleep the mafia meet and plot who they're going to kill etc
So the two people with the non number cards ie jack/joker/ace etc open their eyes and look at the Narrator - so the Narrator know's who they are - another way to do it is to have the mafia separate but I'll get to that later.
So two people have their eyes open they consult who they're going to kill point to the player with their eyes so as not to make sudden movements and go back to "sleep"
Then the Narrator tells the detective to wake up and guess who he thinks the mafia are - he points to someone the narrator nods or shakes their head and then the detective goes back to sleep
Narrator then says "Morning has come and the townspeople awake to see that ...... has been slaughtered, shot, hung whatever in the night -- like I said the more creative your narrator the more interesting it gets
And then the accusations begin -- It's like the salam witch hunt - someone accuses someone else of being Mafia - now the detective if he know's that George is Mafia but doesn't know who the other mafia person is can either remain silent or speak up if he says "'i strongly suggest you put George on trial" the townspeople may think hey John might be the detective and he might no something I dont know - at the same time the Mafia want as many people as the can get dead so they'll just accuse someone and will hopefully convince everyone that its them.
The townspeople will then vote on who's to be lynched and the lynched person then shows everyone his card -- if its a jack/joker then he's mafia, if its a number hes an innocent and if it's an Ace he's the detective.
This keeps going until both mafia have been lynched or until everybody is dead.
Variations are 2 Mafia - black & red -- 2 red mafia, 1 black work separately -- this is especially interesting if the black mafia kills the red mafia and vice-versa
This happened in the first round of one game we played so the narrator just kept killing people just because.
and TRIVIA mafia - the two accused people had to answer trivia questions to be "saved" -- but they could phone a friend