Incredible Wikipedia entry, Twitter comments can still be gold.
A bit more from the entry (what's your guess as to when the FBI broke up the group?):
It was in this gray area of halakha (Jewish law) that ..., a rabbi from Brooklyn, New York, Mendel Epstein, began to advocate for women seeking religious divorces from their husbands. Dubbed "The Prodfather" by the press, due to his boast of using a cattle prod against his victims, Epstein coerced these men to divorce their wives through the use of violence. In ____, Father's Rights activist Monty Weinstein staged a protest with 25 people outside Epstein's home, with some carrying signs that read "Stop Mendel Epstein!"