The present invention provides a system and method for detecting collusion in online gaming involving a plurality of players, the method comprising storing game information data and game action data on every action in every game for every player in the online gaming database, performing a player action analysis of correlated actions between a pair of online game players and storing data from the player action analysis in a user action database, employing one or more Bayesian Network graphical models to determine a likelihood of conditional behavior between the pair of online game players, computing individual scores for the Bayesian Network graphical models and comparing the score of a collusional model with that of a non-collusional model.