Halakhah for Sotah 90:9

From the laws of the commandment is that which they, may their memory be blessed, said (Sotah 45b) that Jerusalem does not bring a beheaded calf; as it is stated about this, "on the land that the Lord, you God, gives to you" - and Jerusalem was not divided [by] the tribes. And likewise we do not bring a calf if it is found near the border or [near] a town the majority of which are gentiles, as the assumption is that the gentiles killed him. [If] there were two towns there, one of which was closer and one of which was not closer but there is a greater multitude of people there than in the closer one, we go after the further one that has many [people] - as so did they, may their memory be blessed, say in the Gemara (Bava Batra 23b), "[In a case where one can decide based on] majority or proximity, one goes after majority." And even though majority and proximity are both from Torah writ - meaning that the Torah commanded us to consider proximity and majority - majority is preferred. And from where we measure, from the nostrils of the killed; the law of its beheading, which is with a kofits (a large knife) from behind it; the law of the washing of the hands; the law of [when] the body is found in one place and the head is found in another place; the law of that which they said (Sotah 44b-45a), "'Slain person' and not strangled person, 'on the land' and not covered by a pile of stones, 'fallen' and not hanging on a tree, 'in the field' and not floating on top of the water"; and the rest of its details are [all] elucidated in the last chapter of Tractate Sotah (see Mishneh Torah, Laws of Murderer and the Preservation of Life 6).