Chofetz Chaim Daily 28 Cheshvan 7:3 Asur to believe LH even if heard from two people. They are wicked people who we do not trust to spoil a good person’s name because they are speaking LH. 7:4 Asur to believe a rumor that ploni did an aveira, may suspect until clarified. One may relate it in conversation, but not purposely spread it.
Chofetz Chaim Daily 29 Cheshvan 7:5 Mutar to believe LH about someone who is known to constantly transgress serious sins. 7:6 If someone degrades himself and another, you may believe it about himself but not the other.