4Game

1. Coop with random before game starts and make sure everybody knows that you both are running together no matter what.
2. If the body is found, then you prove everyone that you and random are clean, otherwise one of you two is the impostor.
3. While discussion goes on, make random pair with another person and you pair with other one.
4. 2 "clean" people are making sure other two are clear. If impostor is one of them, then they are handcuffed as making any move means revealing, if they aren't an impostor then you have 4 confirmed clean people. Once body is found and nobody in pairs split up, the amount of suspects reduces.
5. Repeat step 3 and 4, but double that.
6. Congrats, it may be hard, but you slowly checked every person until you figured out the impostor.

If the body belongs to one of "clean" people while they were checking somebody – gz, imposter figured out.

I guess I nullified any mindgames and cut the game to something boring.