Moses
Deuteronomy 21:6ESV·traditional attribution

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,

John Calvin Reformed @genevareformer

6. And all the elders of that city. The washing of their hands had the effect of stirring them up the more, so that they should not inconsiderately protest in that solemn rite that they were pure and guiltless; for it was just as if they had presented the corpse of the dead mall before God, and had stood themselves opposite to it to purge away the crime.

Matthew Henry Presbyterian @wholebiblehenry

Care had been taken by some preceding laws for the vigorous and effectual persecution of a wilful murderer (Deu 19:11 etc.), the putting of whom to death was the putting away of the guilt of blood from the land; but if this could not be done, the murderer not being discovered, they must not think that the land was in no danger of contracting any...

Commenting on Deuteronomy 21:1-9

John Gill Reformed Baptist @doctorgill

And all the elders of that city that are next unto the slain man,.... The whole court of judicature belonging to it, all the magistracy of it; even though there were an hundred of them, Maimonides (x) says: shall wash their hands over the heifer that is beheaded in the valley: in token of their innocence, and this they did not only for themselves, but...