Murder mysteries can be run for special events such as birthday parties and they can have many themes. There are also professional companies that run them, frequently as interactive dinner theatre.Usually, murder mysteries involve one person running the story and several characters. Around eight characters is normal. Characters can be professional actors, amateur participants or a mix of the two. Scripts can be complex, but usually, they're fairly simple with a biography/character sheet for each participant and a simple story structure with a few plot points and key clues.