Deuteronomy 21:6-8

And all the elders of that city nearest to the slain man shall wash their hands over the heifer whose neck was broken in the valley. Then they shall answer and say, ‘Our hands have not shed this blood, nor have our eyes seen it. Provide atonement, O LORD, for Your people Israel, whom You have redeemed, and do not lay innocent blood to the charge of Your people Israel.’ And atonement shall be provided on their behalf for the blood.