What even is this? The single best way to resolve Cult is to hunt for those that can recruit. Usually, only the leader can, as a Cult that works in a heriditary fashion is extremely difficult to stop (read: impossible). So rather than hunting for the converted, you should hunt for those that started as Cult. And yes, assuming the Cult can still convert I am suggesting the Cult started with more than one player. Flavour wise, probably Lumine and Dainslief. Traditionally, killing the recruiting ability of Cult removes all the Culted from the game, but in any case, once it has stopped growing, if that doesn't eliminate them, you then look for those whos attitudes or play changed at points they were potentially recruited. Even slight differences.
My point is, building up a PoE isn't really all that worthwhile here, as the Cult's very design philosophy is to make it as hard as possible to confirm players. It's why Cults are far greater threats than Mafia, and why Cultafia's, unless restricted heavily, are typically considered "Bastard".