How to solve a murder mystery logic puzzle
One of the suspects is the killer. Each suspect had exactly one weapon and was in exactly one place, and no two suspects shared any of them. Everyone tells the truth, but nobody tells all of it.
Six steps to the killer
- Read the story and every statementThe statements are your clues. They sit on the page after the story, numbered 1, 2, 3 and so on.
- Mark the evidence sheetEach square pairs two things, such as a suspect and a weapon. Put an X when a statement rules a pair out, and an O when you know a pair is true. The murder board lists everyone's traits: height, hand, eyes, hair, what a weapon weighs and is made of, and whether a place is indoors.
- After every O, clear its row and columnAn O means nobody else had that weapon and that suspect had nothing else, so every other square in its row and column of that block gets an X.
- Start with the statements that name someoneThen look up the traits for the rest. A weapon was wherever its owner was: if Mabel had the rope and was in the cellar, the rope was in the cellar too.
- Stuck? Ask "what if?"In harder cases, pick a square with two choices left in its row and suppose one is true. If the statements then contradict each other, that square is an X.
- Name the killer, then pin itThe evidence fits exactly one suspect. On the murder board, run a string from each suspect to their weapon and their place. The solutions at the back explain every step.
| rope | vase | pistol | |
|---|---|---|---|
| Mabel | X | X | O |
| Ivo | X | ||
| Nell | X |
An example from the book: statements ruled out the rope and the vase for Mabel, so the pistol was hers. Nobody else had the pistol, so the rest of its column gets an X.
Every case plays fair
Every clue you need is on the page. There is no outside knowledge, no trick wording and no guessing.
Each case was checked by computer against every possible answer, so exactly one suspect fits the statements. If your answer fits every statement, it is the right one.
Cases start with three suspects. At the top rank, Chief Inspector, you must also work out each suspect's motive.
Try it on a real case
Case 30 is free to print, with the full solution. The other 49 are in the paperback.