- 1 Sane Cop - Gets accurate investigation results.
- 1 Insane Cop - Gets the opposite investigation result.
- 1 Paranoid Cop - Always gets a "Guilty" result.
- 1 Naive Cop - Always gets an "Innocent" result.
- 1 Mafia Goon
Cops are not told which type they are at the beginning, and must figure out their sanity as the game progresses.
There is a Night 0 for Cops to make their first investigation. The Mafia player kills on every night after Night 0.
The strategy to Dethy lies in discovering which of the five "cops" is lying about his investigation results by first determining the possible sanities for each player. Dethy is often criticized for being more of a logic puzzle than a game of Mafia for this reason.
MafiaBot has a Dethy variant programmed in it.