Sleuthic

The Black Files · October 3, 2026 · Difficulty: Cadet

Black File #106 — SolutionManifest

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The case

Fabian Quinn, doorman, was found dead at Ellery Court Apartments at 3:35 PM. Seven people were at the scene. Exactly one of them was alone with Fabian in the same zone.

The evidence (11 clues)
  1. Grace was standing on the stairs.
  2. Aaron was in Apartment 3B.
  3. Deborah was standing on the floor.
  4. Aaron was standing on the stairs.
  5. Beth was standing on the stairs.
  6. Ernest was standing on the floor.
  7. Grace was in the Laundry Room.
  8. Ernest was the westernmost person at the scene.
  9. Connie was the easternmost person at the scene.
  10. Fabian was the northernmost person at the scene.
  11. Connie was the southernmost person at the scene.

The answer

The killer: Grace Trask, alone with Fabian Quinn in the Laundry Room.

Fixing rows and columns from the extreme-position clues cascades through the board and leaves Grace alone with Fabian in the Laundry Room.

Step-by-step deduction

  1. Before placing anyone, each clue eliminates cells:
  2. • Aaron: was in Apartment 3B; was on the stairs; row 7 already belongs to Connie; column E already belongs to Grace; row 5 belongs to Ernest. Only F6 is left.
  3. • Beth: was on the stairs; row 7 already belongs to Connie; row 3 already belongs to Grace; column E already belongs to Grace; column F belongs to Aaron; column A belongs to Ernest. Only B2 is left.
  4. • Connie: was the easternmost person of all, and since there is one person per column somebody occupies column G: that is Connie; was the southernmost person of all, and since there is one person per row somebody occupies row 7: that is Connie. Only G7 is left.
  5. • Deborah: was standing on the floor; row 7 already belongs to Connie; column G already belongs to Connie; row 3 already belongs to Grace; column E already belongs to Grace; column F belongs to Aaron; row 5 belongs to Ernest; row 1 belongs to Fabian; nobody else can occupy row 4, so it must be Deborah. Only C4 is left.
  6. • Ernest: was standing on the floor; was the westernmost person of all, and since there is one person per column somebody occupies column A: that is Ernest; row 7 already belongs to Connie. Only A5 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 G already belongs to Connie; column E already belongs to Grace; column F belongs to Aaron; column A belongs to Ernest; nobody else can occupy column D, so it must be Fabian. Only D1 is left.
  8. • Grace: was on the stairs; was in the Laundry Room. Only E3 is left.
  9. That already places Connie at G7, Grace at E3, Aaron at F6, Beth at B2, Deborah at C4, Ernest at A5 and Fabian at D1.
  10. With all seven placed, the only people in the Laundry Room are Fabian and Grace: Grace was alone with the victim.
Solved map of Black File #106: Aaron F6, Beth B2, Connie G7, Deborah C4, Ernest A5, Fabian D1, Grace E3
The solved map: Aaron F6, Beth B2, Connie G7, Deborah C4, Ernest A5, Fabian D1, Grace E3.

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