Can you please explain what Murder Mystery is? You can't expect everyone to have heard of it (I haven't).
Murder mystery games are generally party games wherein one of the partygoers is secretly, and unknowingly, playing a murderer, and the other attendees must determine who among them is the criminal. This may involve the actual 'murders' of guests throughout the game, or may open with a 'death' and have the rest of the time devoted to investigation. Murder mystery games may also refer to public performances in venues for events, team building or corporate entertainment, where the suspects are played by actors, and the role of detectives falls to the other guests. Dinner party murder mystery games are generally played with small groups of individuals, e.g. 6-20. Murder mystery events for larger groups are usually run for numbers between 20 and 250 attendees, though events can be run with 400+ in attendance.