Sleuthic

The Black Files · November 7, 2026 · Difficulty: Rookie

Black File #149 — SolutionLockdown

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The case

Gail Quinn, informant, was found dead at Ninth Precinct at 11:15 PM. Seven people were at the scene. Exactly one of them was alone with Gail in the same zone.

The evidence (8 clues)
  1. Diane was in the Front Desk.
  2. Colin was in the Front Desk.
  3. Elena was sitting on a sofa.
  4. Frances was standing on stairs.
  5. Colin was the northernmost person at the scene.
  6. Anthony was the southernmost person at the scene.
  7. Benjamin and Elena were in the same zone.
  8. Benjamin was the westernmost person at the scene.

The answer

The killer: Anthony Coleman, alone with Gail Quinn in the Squad Room.

Fixing rows and columns from the extreme-position clues cascades through the board and leaves Anthony alone with Gail in the Squad Room.

Step-by-step deduction

  1. Before placing anyone, each clue eliminates cells:
  2. • Anthony: was the southernmost person of all, and since there is one person per row somebody occupies row 7: that is Anthony; column C already belongs to Elena; column B belongs to Diane; column D already belongs to Colin; column E belongs to Frances. Only F7 is left.
  3. • Benjamin: was in the same zone as Elena, and Elena can only be in the Squad Room, the Interview Room or the Evidence Locker; was the westernmost person of all, and since there is one person per column somebody occupies column A: that is Benjamin; row 6 already belongs to Elena. Only A5 is left.
  4. • Colin: was in the Front Desk; was the northernmost person of all, and since there is one person per row somebody occupies row 1: that is Colin; column A belongs to Benjamin; column C already belongs to Elena; column B belongs to Diane. Only D1 is left.
  5. • Diane: was in the Front Desk; column A belongs to Benjamin; row 1 belongs to Colin; column C already belongs to Elena; row 4 already belongs to Gail; row 2 belongs to Frances. Only B3 is left.
  6. • Elena: was sitting on the sofa; row 7 belongs to Anthony; column A belongs to Benjamin; row 1 belongs to Colin; was in the same zone as Benjamin, and Benjamin can only be in the Interview Room. Only C6 is left.
  7. • Frances: was on the stairs; row 7 belongs to Anthony; column A belongs to Benjamin; column C already belongs to Elena; row 5 belongs to Benjamin; only Gail and the killer were in the crime zone (the Squad Room), and those are already Anthony and Gail; column D already belongs to Colin. Only E2 is left.
  8. • Gail: Gail cannot be in the Front Desk: the crime zone holds exactly two people and Colin and Diane are already there, and with Gail that would be more than two; row 7 belongs to Anthony; column A belongs to Benjamin; row 1 belongs to Colin; Gail cannot be in the Interview Room: the crime zone holds exactly two people and Benjamin and Elena are already there, and with Gail that would be more than two; row 6 already belongs to Elena; row 5 belongs to Benjamin; nobody else can occupy column G, so it must be Gail. Only G4 is left.
  9. That already places Elena at C6, Benjamin at A5, Colin at D1, Gail at G4, Anthony at F7, Diane at B3 and Frances at E2.
  10. With all seven placed, the only people in the Squad Room are Gail and Anthony: Anthony was alone with the victim.
Solved map of Black File #149: Anthony F7, Benjamin A5, Colin D1, Diane B3, Elena C6, Frances E2, Gail G4
The solved map: Anthony F7, Benjamin A5, Colin D1, Diane B3, Elena C6, Frances E2, Gail G4.

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