The Black Files · October 20, 2026 · Difficulty: Specialist
Black File #131 — SolutionLedger Line
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The case
Gordon Whitaker, cleaner, was found dead at First Meridian Bank at 12:50 AM. Seven people were at the scene. Exactly one of them was alone with Gordon in the same zone.
The evidence (8 clues)
- Alvin was sitting on a sofa.
- Elena was standing on stairs.
- Deborah was sitting on a sofa.
- Beth was standing on stairs.
- Claire was the westernmost person at the scene.
- Deborah and Elena were in the same zone.
- Claire was the southernmost person at the scene.
- Felicia was the easternmost person at the scene.
The answer
The killer: Beth Underwood, alone with Gordon Whitaker in the Vault Anteroom.
Nothing is forced until you test Elena at E2, D6 or E6: every wrong cell leaves someone with no possible cell. With Elena at E2 the rest cascades and leaves Beth alone with Gordon in the Vault Anteroom.
Step-by-step deduction
- Before placing anyone, each clue eliminates cells:
- • Claire: was the westernmost person of all, and since there is one person per column somebody occupies column A: that is Claire; was the southernmost person of all, and since there is one person per row somebody occupies row 7: that is Claire. Only A7 is left.
- • Beth: was on the stairs; row 7 already belongs to Claire; column A already belongs to Claire; column G belongs to Felicia; nobody else can occupy column C, so it must be Beth. Remaining: C1 and C3.
- • Elena: was on the stairs; was in the same zone as Deborah, and Deborah can only be in the Teller Line, the Manager's Office or the Employee Lounge; row 7 already belongs to Claire; column A already belongs to Claire; column G belongs to Felicia. Remaining: E2, D6 and E6.
- • Felicia: was the easternmost person of all, and since there is one person per column somebody occupies column G: that is Felicia; row 7 already belongs to Claire. Remaining: G2, G3, G4 and G6.
- • Alvin: was sitting on the sofa; row 7 already belongs to Claire; column A already belongs to Claire; column G belongs to Felicia. Remaining: D1, E3, E4, E5 and F6.
- • Deborah: was sitting on the sofa; row 7 already belongs to Claire; column A already belongs to Claire; column G belongs to Felicia. Remaining: D1, E3, E4, E5 and F6.
- • Gordon: row 7 already belongs to Claire; column A already belongs to Claire; column G belongs to Felicia; nobody else can occupy column B, so it must be Gordon. Remaining: B1, B2, B3, B4 and B5.
- That already places Claire at A7.
- At this point no cell is forced. Time to test a hypothesis. Try Elena, who can only be at E2, D6 or E6.
- – Elena at E2: everything fits: it yields Deborah at D1, Gordon at B5, Alvin at F6, Beth at C3 and Felicia at G4.
- – Elena at D6: Deborah is left with no possible cell. Impossible.
- – Elena at E6: Deborah is left with no possible cell. Impossible.
- So Deborah goes to D1, Elena goes to E2, Gordon goes to B5, Alvin goes to F6, Beth goes to C3 and Felicia goes to G4.
- With all seven placed, the only people in the Vault Anteroom are Gordon and Beth: Beth was alone with the victim.
