Deuteronomy 21:9
So shalt thou put away the guilt of innocent blood from among you, when thou shalt do that which is right in the sight of the LORD. So shalt thou put away the guilt of innocent blood from among you, when thou shalt do that which is right in the sight of the LORD.
The guilt of innocent blood is put away from among the people when they do what is right in the sight of the Lord. Its setting is a murder discovered with the killer unknown, in which the elders are to hold a public ceremony declaring their rejection of the crime and praying that the victim's blood not be charged to the people. That ceremony does not excuse negligence, for rulers and others who fail to seek justice or who shield the guilty share in the evil deed. The verse therefore calls for diligent effort to establish the facts and for impartial action against wrongdoing.