How do I add the suspects of my mystery?

From version 1.9.22, open the Codex from the book's page, choose Mystery and find Suspects. Press "Add a suspect", pick the character, then write their motive, opportunity and alibi. Say whether the alibi holds or is a lie, and in "cleared in chapter" the chapter where the story rules them out (leave it empty for a suspect who stays suspected until the end). Three suspects or more keep the reader guessing. The culprit must be among the suspects: Fair play warns you if they are not. Press "Save the board".