Sleuthic

The Black Files · October 11, 2026 · Difficulty: Detective

Black File #122 — SolutionDock A

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The case

Curtis Ibarra, fisherman, was found dead at Harbor Point Marina at 3:35 PM. Seven people were at the scene. Exactly one of them was alone with Curtis in the same zone.

The evidence (8 clues)
  1. Deborah was standing on stairs.
  2. Gina was standing on the floor.
  3. Alvin was standing on the floor.
  4. Deborah was in the Fuel Station.
  5. Bonnie and Fabian were in the same zone.
  6. Fabian was the northernmost person at the scene.
  7. Alvin and Edith were in the same zone.
  8. Alvin was the easternmost person at the scene.

The answer

The killer: Gina Brennan, alone with Curtis Ibarra in the Harbormaster's Shed.

Fixing rows and columns from the extreme-position clues cascades through the board and leaves Gina alone with Curtis in the Harbormaster's Shed.

Step-by-step deduction

  1. Before placing anyone, each clue eliminates cells:
  2. • Alvin: was standing on the floor; was the easternmost person of all, and since there is one person per column somebody occupies column G: that is Alvin; row 5 already belongs to Deborah; row 3 already belongs to Edith. Only G2 is left.
  3. • Bonnie: row 5 already belongs to Deborah; column C already belongs to Deborah; column G belongs to Alvin; row 1 belongs to Fabian; was in the same zone as Fabian, and Fabian can only be in Dock A or the Boat Yard; row 3 already belongs to Edith; row 2 belongs to Alvin. Only A4 is left.
  4. • Curtis: row 5 already belongs to Deborah; column C already belongs to Deborah; column G belongs to Alvin; row 1 belongs to Fabian; Curtis cannot be in Dock A: the crime zone holds exactly two people and Alvin and Edith are already there, and with Curtis that would be more than two; row 3 already belongs to Edith; column F already belongs to Edith; row 2 belongs to Alvin; row 4 belongs to Bonnie; column A belongs to Bonnie; nobody else can occupy column B, so it must be Curtis; row 6 belongs to Gina. Only B7 is left.
  5. • Deborah: was on the stairs; was in the Fuel Station. Only C5 is left.
  6. • Edith: row 5 already belongs to Deborah; column C already belongs to Deborah; column G belongs to Alvin; row 1 belongs to Fabian; was in the same zone as Alvin, and Alvin can only be in Dock A. Only F3 is left.
  7. • Fabian: was the northernmost person of all, and since there is one person per row somebody occupies row 1: that is Fabian; column C already belongs to Deborah; column G belongs to Alvin; column F already belongs to Edith; column A belongs to Bonnie; was in the same zone as Bonnie, and Bonnie can only be in the Boat Yard. Only D1 is left.
  8. • Gina: was standing on the floor; row 5 already belongs to Deborah; column C already belongs to Deborah; column G belongs to Alvin; row 1 belongs to Fabian; row 3 already belongs to Edith; row 2 belongs to Alvin; row 4 belongs to Bonnie; column D already belongs to Fabian. Only E6 is left.
  9. That already places Deborah at C5, Edith at F3, Alvin at G2, Bonnie at A4, Fabian at D1, Curtis at B7 and Gina at E6.
  10. With all seven placed, the only people in the Harbormaster's Shed are Curtis and Gina: Gina was alone with the victim.
Solved map of Black File #122: Alvin G2, Bonnie A4, Curtis B7, Deborah C5, Edith F3, Fabian D1, Gina E6
The solved map: Alvin G2, Bonnie A4, Curtis B7, Deborah C5, Edith F3, Fabian D1, Gina E6.

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