The players sit in a circle facing inwards. One player, the detective, is taken away where he can not see or hear the others. One of the players in the circle is designated as the murderer. Put one piece of paper in a bowl for each player and mark one with an 'X'. Have someone take the bowl around and have each player take one, look at it and then replace it in the bowl. The player with the X is the murderer.
The players decide a secret signal. This could be a pointing finger, a wink, a twitch of the nose etc. The detective is then returned to the circle where he must guess the identity of the murderer before the murderer kills everyone by using the secret signal. If any of the players detects the signal coming from the murderer he must "die" in some dramatic fashion. The detective only has a limited number of guesses in which to guess the identity of the murderer. Three guesses is standard. If the detective fails to guess in time, the murderer takes his place and play continues anew.