Rav Nahman states the importance of true tzadikim [saints] but also brings u the problem of people that are famous for being great tzadikim but in fact are agents from the dark side, In one Torah lesson Rav Nahman calls these phony tzadikim  מפורסמים של שקר [famous frauds] and Rav Israel Odeser said ''If famous then a fraud''.

[That means that people that are famous a being holy and righteous you must know that they are frauds ]