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Case 42: who took the Sacred Scroll?
During last night's private gala at the library, a guest must have gotten a little too close to the Sacred Scroll, on display in the Restoration Room, because it was gone by morning. The guest list is short; so is the room for error. Help the police unmask the thief.
The board
- 1Lobby
- 2Office
- 3Conference Room
- 4Archive
- 5Café
- 6Reception Area
- 7Restrooms
- 8Restoration Room
- 9Study Room
- 10Periodicals Room
- 11Reading Room
- 12Vault
- Plant: no character can stand on its cell, but the stolen item can be there.
- Seat: anyone can be on it.
- Shelf: no character can stand on its cell, but the stolen item can be there.
- Table: nothing can be on its cell.
- Screen: nothing can be on its cell.
- Window: the blue line on a wall.
Suspects and clues
- IIvan
He's right next to the Conference Room. - CCarla
She's 1 row away from the Reception Area. - WWendy
She's right next to the Lobby. - NNadia
She's next to a screen. - YYusuf
He's in the Restrooms. - OOmar
He's in column H. - DDana
She's not next to any wall. - SSacred Scroll (stolen item)
It's 2 columns away from the Café and 1 column away from the Lobby.
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
- Ivan's clue: He's right next to the Conference Room. 18 cells remain possible.
- Carla's clue: She's 1 row away from the Reception Area. 2 cells remain possible: B3 and A6.
- Wendy's clue: She's right next to the Lobby. 11 cells remain possible.
- Nadia's clue: She's next to a screen. 2 cells remain possible: F5 and G6.
- Yusuf's clue: He's in the Restrooms. 2 cells remain possible: E3 and E4.
- Omar's clue: He's in column H. 8 cells remain possible.
- Dana's clue: She's not next to any wall. 7 cells remain possible.
- The stolen item's clue: It's 2 columns away from the Café and 1 column away from the Lobby. It leaves a single cell: G8.
- The Sacred Scroll can only be on G8. No one else can be in row 8 or column G.
- G6 has already been ruled out, so Nadia can only be on F5. No one else can be in row 5 or column F, and no other character can be in the Archive.
- Every cell still open to Yusuf is in column E, so no one else can be in that column.
- Every cell still open to Omar is in column H, so no one else can be in that column.
- The Sacred Scroll can only be in the Study Room, and Omar is the only character who can still get in there. Since the thief shares a room with the item, Omar must be in the Study Room.
- Proof by contradiction. Suppose Omar were on H9. Following the rules above, there wouldn't be enough rows left for everyone. So Omar is not on H9.
- H2, H3, H4, H5, H6, H7 and H9 have already been ruled out, so Omar can only be on H10.
- Proof by contradiction. Suppose Dana were on C6. Following the rules above, there wouldn't be enough rows left for everyone. So Dana is not on C6.
- G2, G3, H3, C6, D8 and G9 have already been ruled out, so Dana can only be on B9. No one else can be in row 9 or column B, and no other character can be in the Restoration Room.
- B3 has already been ruled out, so Carla can only be on A6. No one else can be in row 6 or column A, and no other character can be in the Conference Room.
- Every other cell the clue allowed has already been ruled out, so Wendy can only be on I7. No one else can be in row 7 or column I, and no other character can be in the Office.
- Every other cell the clue allowed has already been ruled out, so Ivan can only be on C4. No one else can be in row 4 or column C, and no other character can be in the Vault.
- E4 has already been ruled out, so Yusuf can only be on E3.
Conclusion: Omar is the only person sharing the Study Room with the Sacred Scroll, which is on G8. He is the thief.