Hilchos Lashon Hara chapter 7, section 10

If there are devarim nikarim, clear indications the story is true, the law is as follows. If the story even if true can be judged favorably or if it involves lack of good traits or other details explained above in paragraph 7, the principle of devarim nikarim is irrelevant. For we must certainly judge the person favorably if he is an average person and not feel disparaging towards him. If there is no way of judging the matter favorably one may believe the report.