My sibling's 'peeps' are religious nuns and a priest, who had been in a fundamentalist cult like religious house/situation prior to the 1990s. They individually were asked to leave for certain highly dubious behaviors. They entered religious life right outta high school, in each case. They have upped their stakes, in desperation, by (literally) becoming Jim Jones (from the 1970s) like, which allows them to manipulate followers, through dysfunctional manipulation bent on increasing their own power, esp within the group. They use the unquestioning devotion of followers to increase their dependence on the leaders, isolating them from anyone outside, including family--family relationships are sick and need to be broken down or taken away...all the typical signs one would expect, I suppose of people with a difficult past.
When my brother goes to visit them, I warn him "Don't drink the kool-aid!"