New Revised Standard Version
and the judges shall make a thorough inquiry. If the witness is a false witness, having testified falsely against another,

New American Bible
and the judges must investigate it thoroughly. If the witness is a false witness and has falsely accused the other,

Douay-Rheims Bible
And when after most diligent inquisition, they shall find that the false witness hath told a lie against his brother:

And when after most diligent inquisition, they shall find that the false witness hath told a lie against his brother:

diligent

Deuteronomy 13:14 Inquire carefully and diligently, the truth of the thing by looking well into it, and if thou find that which is said to be certain, and that this abomination hath been really committed,

Deuteronomy 17:4 And this is told thee, and hearing it thou hast inquired diligently, and found it to be true, and that the abomination is committed in Israel:

2 Chronicles 19:6,7 And charging the judges, he said: Take heed what you do: for you exercise not the judgment of man, but of the Lord: and whatsoever you judge, it shall redound to you. . . .

Job 19:16 I called my servant, and he gave me no answer, I entreated him with my own mouth.