Clues & Culprits › Archive › Oct 21, 2026 Medium walkthrough
Oct 21, 2026 Full Proof Walkthrough
Every verdict in the Medium case “Three Centimetres at the Post”, in an order where each step is proven by the statements already on file.
Play it first Just a hint, please
This Medium case seats 20 suspects on a 4×5 grid. 16 of them carry a clue; the other 4 only have something to say about themselves. 2 of the steps can only be proven by reading two or more clues together. The order below is one valid route; any order where each verdict is proven when you enter it reaches the same answer.
Spoiler: show the full walkthrough
Start: Ada (A1) begins the case proven a criminal.
Nobody between me and Dev is a criminal.— Ada, trainer (A1)
Step 1: Basil (B1, clerk of the course) is innocent. This follows from Ada’s statement and the verdicts already proven.
Step 2: Cal (C1, bookmaker) is innocent. This follows from Ada’s statement and the verdicts already proven.
Step 3: Dev (D1, bookmaker) is a criminal. This follows from Basil’s statement and the verdicts already proven.
There is exactly one criminal to my right.— Basil, clerk of the course (B1)
Step 4: Freya (B2, stable hand) is innocent. This follows from Cal’s statement and the verdicts already proven.
Greta and I have exactly one criminal neighbor in common.— Cal, bookmaker (C1)
Step 5: Hana (D2, champagne caterer) is innocent. This follows from Cal’s statement and the verdicts already proven.
Step 6: Greta (C2, clerk of the course) is a criminal. This follows from Dev’s statement and the verdicts already proven.
Exactly two of my three neighbors are innocent.— Dev, bookmaker (D1)
Step 7: Jasper (B3, stable hand) is innocent. This follows from Greta’s statement and the verdicts already proven.
Exactly one of Jasper and me is innocent.— Greta, clerk of the course (C2)
Step 8: Ezra (A2, milliner) is a criminal. This follows from Jasper’s statement and the verdicts already proven.
If Ezra is innocent, then I'm a criminal.— Jasper, stable hand (B3)
Step 9: Iris (A3, milliner) is innocent. This follows from Freya’s statement and the verdicts already proven.
Exactly three of my eight neighbors are criminals.— Freya, stable hand (B2)
Step 10: Kira (C3, milliner) is innocent. This follows from Freya’s statement and the verdicts already proven.
Step 11: Mabel (A4, champagne caterer) is a criminal. This follows from Iris’s statement and the verdicts already proven.
Exactly three of my five neighbors are criminals.— Iris, milliner (A3)
Step 12: Nico (B4, milliner) is a criminal. This follows from Ezra’s statement and the verdicts already proven.
Exactly two of us four milliners are criminals.— Ezra, milliner (A2)
Step 13: Percy (D4, bookmaker) is a criminal. This follows from Nico’s statement and the verdicts already proven.
If Percy is innocent, then so am I.— Nico, milliner (B4)
Step 14: Suki (C5, clerk of the course) is innocent. This needs 2 statements together — Kira’s and Percy’s. Assume the opposite verdict and at least one of them breaks.
An even number of my neighbors are innocent.— Kira, milliner (C3)
Exactly one of my five neighbors is a criminal.— Percy, bookmaker (D4)
Step 15: Otto (C4, stable hand) is a criminal. This needs 2 statements together — Mabel’s and Suki’s. Assume the opposite verdict and at least one of them breaks.
Exactly two of my five neighbors are criminals.— Mabel, champagne caterer (A4)
Exactly three of Nico's eight neighbors are criminals.— Suki, clerk of the course (C5)
Step 16: Lena (D3, trainer) is innocent. This follows from Kira’s statement and the verdicts already proven.
Step 17: Queenie (A5, champagne caterer) is innocent. This follows from Otto’s statement and the verdicts already proven.
Exactly two of the four people in the corners are innocent.— Otto, stable hand (C4)
Step 18: Raj (B5, trainer) is a criminal. This follows from Mabel’s statement and the verdicts already proven.
Step 19: Theo (D5, trainer) is innocent. This follows from Percy’s statement and the verdicts already proven.
The final lineup
| A | B | C | D | |
|---|---|---|---|---|
| 1 | Ada criminal | Basil innocent | Cal innocent | Dev criminal |
| 2 | Ezra criminal | Freya innocent | Greta criminal | Hana innocent |
| 3 | Iris innocent | Jasper innocent | Kira innocent | Lena innocent |
| 4 | Mabel criminal | Nico criminal | Otto criminal | Percy criminal |
| 5 | Queenie innocent | Raj criminal | Suki innocent | Theo innocent |
What happened
The judges' photograph was retouched before the judges ever saw it. Otto, a stable hand who had 'repaired' the photo-finish camera twice that season, gave it a third repair that sent its pictures through a laptop in the weighing room, where Raj, a trainer who knew the software inside out, moved Copper Lane forward three centimetres. Ada, his fellow trainer, owned a share of the horse; Greta, clerk of the course, rushed the result through before anyone asked for the raw file. Dev and Percy, the bookmakers, had laid long odds against the other horse. Ezra and Nico spread word in the stands that the favourite was lame, and Mabel kept the stewards' champagne flowing.