Deuteronomy 21:4-5

They and some of the priests will take this cow to a nearby valley where there is a stream, but no crops. Once they reach the valley, the leaders will break the cow's neck. The priests must be there, because the LORD your God has chosen them to be his special servants at the place of worship. The LORD has chosen them to bless the people in his name and to be judges in all legal cases, whether property or injury is involved.