Deuteronomy 19:15-19

“A single witness shall not rise up against a person regarding any wrongdoing or any sin that he commits; on the testimony of two or three witnesses a matter shall be confirmed.

If a malicious witness rises up against a person to testify against him of wrongdoing,

then both people who have the dispute shall stand before the Lord, before the priests and the judges who will be in office in those days.

And the judges shall investigate thoroughly, and if the witness is a false witness and he has testified against his brother falsely,

then you shall do to him just as he had planned to do to his brother. So you shall eliminate the evil from among you.