Pick a level of complexity for the game
Each game level has its own values and requirements and the price varies.
Level 1 mystery:
A traitor among us.
Level one mystery is simple: it is a short game, and all effort is put into the dinner and the music and drinks.
There can be multiple rounds and it is more of a house game with characters. It has been popularised as the game of "werewolf" or "among us".
The number of characters and "bad guys" can change depending on the crowd size and the speed at which people understand the game and the roles, becoming more and more complex with each round if agreed.
Level 2 mystery:
The treasures hunt.
Level 2 Murder mystery is a treasure hunt to find the murderer.
This can be acted in costume and in character to make it more elaborate and complex, the location here is key so if you have a location I can scout beforehand to plan and plant some clues that would be ideal.
The level of the clues is scaled with the number of clues (more clues = harder clues).
Level 3 mystery:
The Olympics
The Olympics is a perfect way to describe level 3 mystery.
It is a series of trials and games based on the theme and the number of people, there can be group challenges and or individual ones depending on the location and the crowd.
Among the players, there will be a killer or a cheater and it would be up to the participants to find who that is.
Level 4 mystery:
The Machiavellian story.
This is the most complex murder mystery and requires an adept audience.
Each and every participant will have a story, with a secret mission, powers, and backstory to act upon.
The story is going to be really complex and full of suspense but we need everyone to be present since all stories are intertwined and need each other to work.
If you ever played D&D it is not so far as a concept.