‏ Deuteronomy 21:6-8

6And all the elders of that city nearest to the slain man ashall wash their hands over the heifer whose neck was broken in the valley, 7and they shall testify, ‘Our hands did not shed this blood, nor did our eyes see it shed. 8Accept atonement, O Lord, for your people Israel, whom you have redeemed, and bdo not set the guilt of innocent blood in the midst of your people Israel, so that their blood guilt be atoned for.’
Copyright information for ESV