Deuteronomy 19:15-19

MLV(i) 15 One witness will not rise up against a man for any iniquity, or for any sin, in any sin that he sins. At the mouth of two witnesses, or at the mouth of three witnesses, will a matter be established.
16 If an unrighteous witness rises up against any man to testify against him of wrong-doing, 17 then both the men, between whom the controversy is, will stand before Jehovah, before the priests and the judges that will be in those days,
18 and the judges will make diligent inquiry. And behold, if the witness is a false witness and has testified falsely against his brother, 19 then you* will do to him, as he had thought to do to his brother. So will you put away the evil from the midst of you.