Sleuthic

The Black Files · October 5, 2026 · Difficulty: Investigator

Black File #116 — SolutionOff the Record

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The case

Daniel Trask, old friend, was found dead at The Aldridge Residence at 6:05 AM. Seven people were at the scene. Exactly one of them was alone with Daniel in the same zone.

The evidence (10 clues)
  1. Adrian was sitting on the sofa.
  2. Elena was standing on the floor.
  3. Frank was the northernmost person at the scene.
  4. Adrian was the southernmost person at the scene.
  5. Frank and Gwen were in the same zone.
  6. Adrian and Colin were in the same zone.
  7. Benjamin was the westernmost person at the scene.
  8. Frank was the easternmost person at the scene.
  9. Benjamin was farther north than Elena.
  10. Elena was farther west than Gwen.

The answer

The killer: Elena Patel, alone with Daniel Trask in the Living Room.

Fixing rows and columns from the extreme-position clues cascades through the board and leaves Elena alone with Daniel in the Living Room.

Step-by-step deduction

  1. Before placing anyone, each clue eliminates cells:
  2. • Adrian: was sitting on the sofa; was the southernmost person of all, and since there is one person per row somebody occupies row 7: that is Adrian; column G already belongs to Frank; column A belongs to Benjamin. Only C7 is left.
  3. • Benjamin: was the westernmost person of all, and since there is one person per column somebody occupies column A: that is Benjamin; was farther north than Elena, and Elena is no farther than row 5; row 1 already belongs to Frank; row 6 belongs to Colin; row 4 belongs to Elena; row 2 belongs to Gwen. Only A3 is left.
  4. • Colin: was in the same zone as Adrian, and Adrian can only be in the Kitchen; column G already belongs to Frank; row 7 belongs to Adrian; column C already belongs to Adrian. Only B6 is left.
  5. • Daniel: Daniel cannot be in the Kitchen: the crime zone holds exactly two people and Adrian and Colin are already there, and with Daniel that would be more than two; row 1 already belongs to Frank; column G already belongs to Frank; column A belongs to Benjamin; row 6 belongs to Colin; Daniel cannot be in the Back Garden: the crime zone holds exactly two people and Frank and Gwen are already there, and with Daniel that would be more than two; column C already belongs to Adrian; column B belongs to Colin; row 4 belongs to Elena; column D belongs to Elena; nobody else can occupy row 5, so it must be Daniel. Only F5 is left.
  6. • Elena: was standing on the floor; Benjamin was farther north than Elena, and Benjamin is at least at row 2; was farther west than Gwen, and Gwen is no farther than column F; row 7 belongs to Adrian; column A belongs to Benjamin; row 6 belongs to Colin; column C already belongs to Adrian; column B belongs to Colin. Only D4 is left.
  7. • Frank: was the northernmost person of all, and since there is one person per row somebody occupies row 1: that is Frank; was the easternmost person of all, and since there is one person per column somebody occupies column G: that is Frank. Only G1 is left.
  8. • Gwen: was in the same zone as Frank, and Frank can only be in the Back Garden; Elena was farther west than Gwen, and Elena is at least at column A; row 1 already belongs to Frank; column G already belongs to Frank; column C already belongs to Adrian; column D belongs to Elena; nobody else can occupy column E, so it must be Gwen. Only E2 is left.
  9. That already places Frank at G1, Adrian at C7, Benjamin at A3, Colin at B6, Daniel at F5, Elena at D4 and Gwen at E2.
  10. With all seven placed, the only people in the Living Room are Daniel and Elena: Elena was alone with the victim.
Solved map of Black File #116: Adrian C7, Benjamin A3, Colin B6, Daniel F5, Elena D4, Frank G1, Gwen E2
The solved map: Adrian C7, Benjamin A3, Colin B6, Daniel F5, Elena D4, Frank G1, Gwen E2.

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