Sounds like a regular game of mafia or werewolves, which basically just requires someone to run it and some means of communication, whether it be in-person, IRC, forum, or some other chat application (there are more 'formal' versions of it in the form of board games or video games, like town of salem, as well).

Picked up Town of Salem recently. Quite a fun game. Have been pleasantly surprised with a good experience even with random other people most of the time