GEN1294 Even if [a] person [is] more evil than good, but not so evil that he is a chronic sinner, one still should judge this person’s actions favorably whenever there is room to interpret the behavior as moral or immoral.   Chofetz Chaim, Issurei Lashon Hara 3:7. … Nevertheless, Jewish law says that Jews may indeed judge unfavorably a known evil person. … King Solomon already informed us that when a basically evil person seems to be doing something good, we should not believe him. Proverbs 26:25.   Proverbs also says that a righteous person can recognize the cunning ways of someone who is evil, implying that any good that an evil person seems to be doing is sometimes feigned. Proverbs 21:12 The classic example of this can be found in the Torah when Laban, the father of Rachel, whom Jacob had just met at the well, ran out to kiss and hug his long lost relative.  Rashi explains Laban’s intentions behind each seemingly positive action towards Jacob as a means to find and take any jewels that Jacob might have been hiding on his person.  Once a person or group of people have established for themselves a well-deserved reputation as evildoers, it is very difficult undo this characterization and judge their actions favorably, no matter how good they later appear.   AMJV 206-7