Deuteronomy 21:2-8

21:2 your elders and judges must go out and measure how far it is to the cities in the vicinity of the corpse. 21:3 Then the elders of the city nearest to the corpse must take from the herd a heifer that has not been worked – that has never pulled with the yoke – 21:4 and bring the heifer down to a wadi with flowing water, to a valley that is neither plowed nor sown. There at the wadi they are to break the heifer’s neck. 21:5 Then the Levitical priests will approach (for the Lord your God has chosen them to serve him and to pronounce blessings in his name, and to decide every judicial verdict) 21:6 and all the elders of that city nearest the corpse must wash their hands over the heifer whose neck was broken in the valley. 21:7 Then they must proclaim, “Our hands have not spilled this blood, nor have we witnessed the crime. 21:8 Do not blame your people Israel whom you redeemed, O Lord, and do not hold them accountable for the bloodshed of an innocent person.” Then atonement will be made for the bloodshed.