Sleuthic

The Black Files · November 2, 2026 · Difficulty: Cadet

Black File #144 — SolutionThe Loading Dock

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The case

Erica Marsh, security guard, was found dead at Riverside Warehouse at 11:15 PM. Seven people were at the scene. Exactly one of them was alone with Erica in the same zone.

The evidence (10 clues)
  1. Bianca was sitting on a sofa.
  2. Denise was in the Loading Dock.
  3. Gail was sitting in a chair.
  4. Denise was standing on the floor.
  5. Anita was sitting in a chair.
  6. Clifford was standing on stairs.
  7. Frances was in the Cold Storage.
  8. Gail was in the Cold Storage.
  9. Frances was the southernmost person at the scene.
  10. Clifford was the westernmost person at the scene.

The answer

The killer: Clifford Sokolov, alone with Erica Marsh in the Main Aisle.

Fixing rows and columns from the extreme-position clues cascades through the board and leaves Clifford alone with Erica in the Main Aisle.

Step-by-step deduction

  1. Before placing anyone, each clue eliminates cells:
  2. • Anita: was sitting in a chair; row 6 already belongs to Clifford; row 7 already belongs to Frances; column G belongs to Gail; row 2 already belongs to Bianca. Only E1 is left.
  3. • Bianca: was sitting on the sofa; row 6 already belongs to Clifford; column A already belongs to Clifford; row 7 already belongs to Frances; column F already belongs to Frances; nobody else can occupy column B, so it must be Bianca. Only B2 is left.
  4. • Clifford: was on the stairs; was the westernmost person of all, and since there is one person per column somebody occupies column A: that is Clifford. Only A6 is left.
  5. • Denise: was in the Loading Dock; was standing on the floor; nobody else can occupy row 3, so it must be Denise; column E belongs to Anita. Only D3 is left.
  6. • Erica: Erica cannot be in the Cold Storage: the crime zone holds exactly two people and Frances and Gail are already there, and with Erica that would be more than two; row 6 already belongs to Clifford; column A already belongs to Clifford; row 7 already belongs to Frances; column F already belongs to Frances; nobody else can occupy column C, so it must be Erica; Erica cannot be in the Loading Dock: the crime zone holds exactly two people and Anita and Denise are already there, and with Erica that would be more than two; row 2 already belongs to Bianca; row 4 belongs to Gail. Only C5 is left.
  7. • Frances: was in the Cold Storage; was the southernmost person of all, and since there is one person per row somebody occupies row 7: that is Frances. Only F7 is left.
  8. • Gail: was sitting in a chair; was in the Cold Storage; row 6 already belongs to Clifford; row 1 belongs to Anita. Only G4 is left.
  9. That already places Clifford at A6, Frances at F7, Bianca at B2, Anita at E1, Denise at D3, Erica at C5 and Gail at G4.
  10. With all seven placed, the only people in the Main Aisle are Erica and Clifford: Clifford was alone with the victim.
Solved map of Black File #144: Anita E1, Bianca B2, Clifford A6, Denise D3, Erica C5, Frances F7, Gail G4
The solved map: Anita E1, Bianca B2, Clifford A6, Denise D3, Erica C5, Frances F7, Gail G4.

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