Deuteronomy 19:18
and the judges shall make diligent inquisition; and behold, if the witness is a false witness, and has testified falsely against his brother,
World English Bible (Public Domain)
In context
Before · Deuteronomy 19:16–17
16If an unrighteous witness rises up against any man to testify against him of wrongdoing, 17then both the men, between whom the controversy is, shall stand before the LORD, before the priests and the judges who shall be in those days;
18and the judges shall make diligent inquisition; and behold, if the witness is a false witness, and has testified falsely against his brother,