Deuteronomy 21:6

3 and it shall be, that the city which is nearest unto the slain man, even the elders of that city shall take a heifer of the herd, which hath not been wrought with, and which hath not drawn in the yoke;

4 and the elders of that city shall bring down the heifer unto a valley with running water, which is neither plowed nor sown, and shall break the heifer’s neck there in the valley.

5 And the priests the sons of Levi shall come near; for them Jehovah thy God hath chosen to minister unto him, and to bless in the name of Jehovah; and according to their word shall every controversy and every stroke be.

6 And all the elders of that city, who are nearest unto the slain man, shall wash their hands over the heifer whose neck was broken in the valley;

7 and they shall answer and say, Our hands have not shed this blood, neither have our eyes seen it.

8 Forgive, O Jehovah, thy people Israel, whom thou hast redeemed, and suffer not innocent blood to remain in the midst of thy people Israel. And the blood shall be forgiven them.

9 So shalt thou put away the innocent blood from the midst of thee, when thou shalt do that which is right in the eyes of Jehovah.