Clues must be created which, taken together, point to only one person: the killer. But if every clue points to only that one person, the mystery will be too easy. Each individual clue should implicate several people, so that the murderer can only be revealed by a process of elimination. Only one person fits every clue: the murderer.

For example, in my show The Dying Old Man on the Flying Trapeze the following clues are revealed:

• The killer had to have knowledge of trapeze rigging. (This implicates characters Esmerelda, Sarasota, Superthud the Human Cannonball, Spunky the Clown, and Nimrod the Strongman. Five out of six.)
• The killer had to have been one of a group that went to a bar with the victim the previous night (Esmerelda, Sarasota, Superthud, Nimrod, and Leo the lion tamer).
• The killer had rosin on his/her hands (Esmerelda, Sarasota, Superthud, Spunky, and Nimrod)
• The killer knew that one particular lion would attack anyone wearing the same brand of perfume the lion tamer's ex-wife used. (Superthud, Spunky, and Leo).
• The killer had posession of a bottle of that brand of perfume (Superthud, Leo, Sarasota).
• The killer had unseen access to the trapeze rigging during the show (Superthud, Spunky.)

Clues can be ploted out, and the relationships easily understood, by making a simple chart of which clues implicate who.

A chart for "The Dying Old Man on the Flying Trapeze" looks like this:

	Esmerelda	Sarasota	Superthud	Spunky	Leo	Nimrod
Uses Rosin
Rigging skill
Rigging Access
Went to Bar
Perfume access
Knew about Lion

Only one character is implicated by every clue -- Superthud, the murderer.

A chart like this also makes it easy to change the murderer in subsequent shows. By adding a few lines of dialogue to the new killer's part and changing a few of the previous killer's, the clues can be adjusted so as to point to a different person.

It is also useful to plant or select some minor piece of trivia within the play (such as the name of the Chinese firewalker mentioned in The Dying Old Man On the Flying Trapeze) that can be used as a tie-breaker question should several people guess the murderer, so you can narrow down the field.

Generally, clues will fall into these few categories --

1. Means. The killer must have been capable of actually performing the act. Clues in this category relate to the murderer's access to the murder weapon (ownership of the gun, knife, or blunt instrument used, having keys to the car that ran over poor Uncle Herbert, etc.), knowledge of the method (having special information about a poison, knowing which wire to boobytrap on a trapeze, marksmanship skill, etc.), or physical ability (a quadriplegic could not have whacked six foot tall Maxwell on the top of the head with a garden hoe, the acrophobic Leo could not have climbed the rigging high enough to sabotage the fatal equipment, etc.).
2. Opportunity. The killer had to get a chance to pull the murder off. Clues in this area may either provide an alibi for someone, and thus clear them, or else place them at the scene of the crime in an incriminating way. If the killer must have had five minutes alone with Samantha in order to strangle her, anyone with five unaccounted for minutes becomes instantly suspect.
3. Circumstantial evidence. These are the miscellaneous clues which are meaningless unless put in context with the crime scene. A particular brand of cigarette was found near the body -- and the suspect smokes that brand. A red hair was found on the blonde victim’s collar. Or a woman was seen leaving the scene of the crime, and, it turns out, this male suspect is a cross-dresser.
4. Physical evidence. Fingerprints, surveillance photos or tapes, blood typing -- unambiguous details pointing to one, and only one, person.
5. Miscellaneous pointers. The little hints derived from the victim's last words, or from a cryptic anonymous tip, or by solving a riddle posed by the too confident killer.

Clues should usually be inserted into the play subtly, as the by-product of a conversation, not the main point, so as to maintain the challenge. Information may be broken up, so that the full significance of a minor point does not become apparent until later. If we learn in one scene that a particular character always wears spike heels, we should not find out until several scenes later that spike heel tracks were found beside the body.

Next: Scene Structure