Sleuthic

The Black Files · October 10, 2026 · Difficulty: Detective

Black File #121 — SolutionGrace Period

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The case

Esther Winters, clinic director, was found dead at Lakeside Clinic at 7:10 AM. Seven people were at the scene. Exactly one of them was alone with Esther in the same zone.

The evidence (8 clues)
  1. David was standing on the floor.
  2. Clifford was standing on the floor.
  3. Gregory was sitting in a chair.
  4. Alvin was standing on stairs.
  5. Blake and David were in the same zone.
  6. Franklin was the northernmost person at the scene.
  7. Blake and Clifford were in the same zone.
  8. David was the southernmost person at the scene.

The answer

The killer: Gregory Trask, alone with Esther Winters in the Exam Room 2.

Fixing rows and columns from the extreme-position clues cascades through the board and leaves Gregory alone with Esther in Exam Room 2.

Step-by-step deduction

  1. Before placing anyone, each clue eliminates cells:
  2. • Alvin: was on the stairs; row 7 already belongs to David; nobody else can occupy row 2, so it must be Alvin. Only E2 is left.
  3. • Blake: row 7 already belongs to David; column B already belongs to David; row 1 belongs to Franklin; was in the same zone as David, and David can only be in the Waiting Room; column E already belongs to Alvin; row 5 belongs to Clifford; column C belongs to Clifford. Only D6 is left.
  4. • Clifford: was standing on the floor; row 7 already belongs to David; column B already belongs to David; row 1 belongs to Franklin; was in the same zone as Blake, and Blake can only be in the Waiting Room; column E already belongs to Alvin. Only C5 is left.
  5. • David: was standing on the floor; was the southernmost person of all, and since there is one person per row somebody occupies row 7: that is David. Only B7 is left.
  6. • Esther: row 7 already belongs to David; column B already belongs to David; row 1 belongs to Franklin; Esther cannot be in the Waiting Room: the crime zone holds exactly two people and Blake, Clifford and David are already there, and with Esther that would be more than two; nobody else can occupy row 3, so it must be Esther; nobody else can occupy column G, so it must be Esther. Only G3 is left.
  7. • Franklin: was the northernmost person of all, and since there is one person per row somebody occupies row 1: that is Franklin; column B already belongs to David; nobody else can occupy column A, so it must be Franklin. Only A1 is left.
  8. • Gregory: was sitting in a chair; row 7 already belongs to David; column B already belongs to David; row 1 belongs to Franklin; nobody else can occupy row 4, so it must be Gregory; column E already belongs to Alvin. Only F4 is left.
  9. That already places David at B7, Alvin at E2, Esther at G3, Franklin at A1, Blake at D6, Clifford at C5 and Gregory at F4.
  10. With all seven placed, the only people in Exam Room 2 are Esther and Gregory: Gregory was alone with the victim.
Solved map of Black File #121: Alvin E2, Blake D6, Clifford C5, David B7, Esther G3, Franklin A1, Gregory F4
The solved map: Alvin E2, Blake D6, Clifford C5, David B7, Esther G3, Franklin A1, Gregory F4.

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