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Case 26: who took the Royal Opal?

Difficulty: ★★★★☆ · Board 8×8 · 7 suspects

A routine inventory at the museum has revealed that the Royal Opal, officially listed as being in the Inner Courtyard, is nowhere to be found. The insurance company won't pay a cent without a named culprit, so the pressure to solve this is real. Help the police unmask the thief.

The board

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Suspects and clues

Remember the rules: no two suspects (nor the item) ever share a row or a column, each character is in a different room, and the thief is the only one sharing a room with the stolen item. Unsure? Read how to play and the clue types.

Solution

Try it yourself first: pen and paper are enough. When you want to check, open the reasoned solution.

Show the step-by-step solution
  1. Dana's clue: She's in the Café. 3 cells remain possible: F5, G5 and G6.
  2. Martha's clue: She's right next to the Workshop. 16 cells remain possible.
  3. Gustavo's clue: He's next to a shelf. 5 cells remain possible: G2, F3, G4, B7 and A8.
  4. Peter's clue: He's 3 rows away from the Workshop. 2 cells remain possible: A8 and C8.
  5. Aisha's clue: She's 1 column away from the Restrooms. It leaves a single cell: C1.
  6. Ines's clue: She's 1 column away from the Inner Courtyard and in column B. It leaves a single cell: B2.
  7. Boris's clue: He's in row 7. 7 cells remain possible.
  8. The stolen item's clue: It's in a corner. 38 cells remain possible.
  9. Aisha can only be on C1. No one else can be in row 1 or column C, and no other character can be in the Inner Courtyard.
  10. C8 has already been ruled out, so Peter can only be on A8. No one else can be in row 8 or column A, and no other character can be in the Lobby.
  11. Ines can only be on B2. No one else can be in row 2 or column B, and no other character can be in the Workshop.
  12. Every cell still open to Martha is in column D, so no one else can be in that column.
  13. Every cell still open to Boris is in row 7, so no one else can be in that row.
  14. The item must share its room with one character: the thief. No character can be in the Security Room and the Exhibition Hall any more, so the Royal Opal isn't there either.
  15. There are as many suspects (counting the item) as columns, so each column holds exactly one. Only Boris can still reach column H, so that is where he must be.
  16. A7, B7, D7, E7, F7 and G7 have already been ruled out, so Boris can only be on H7.
  17. There are as many suspects (counting the item) as columns, so each column holds exactly one. Only the Royal Opal can still reach column E, so that is where it must be.
  18. There are as many suspects (counting the item) as rows, so each row holds exactly one. Only Dana can still reach row 6, so that is where she must be.
  19. F5 and G5 have already been ruled out, so Dana can only be on G6. No one else can be in row 6 or column G, and no other character can be in the Café.
  20. G2, G4, B7 and A8 have already been ruled out, so Gustavo can only be on F3. No one else can be in row 3 or column F, and no other character can be in the Storage Room.
  21. The item must share its room with one character: the thief. No character can be in the Cloakroom any more, so the Royal Opal isn't there either.
  22. Every other cell the clue allowed has already been ruled out, so the Royal Opal can only be on E4. No one else can be in row 4 or column E.
  23. Every other cell the clue allowed has already been ruled out, so Martha can only be on D5.

Conclusion: Martha is the only person sharing the Archive with the Royal Opal, which is on E4. She is the thief.

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