Pausanias Description of Greece 1.24.4

[4] and there are statues of Zeus, one made by Leochares ¹ and one called Polieus (Urban), the customary mode of sacrificing to whom I will give without adding the traditional reason thereof. Upon the altar of Zeus Polieus they place barley mixed with wheat and leave it unguarded. The ox, which they keep already prepared for sacrifice, goes to the altar and partakes of the grain. One of the priests they call the ox-slayer, who kills the ox and then, casting aside the axe here according to the ritual runs away. The others bring the axe to trial, as though they know not the man who did the deed.

[4] also, there is a statue [ agalma] of Zeus, one made by Leokhares 83

and another one called Polieus [‘of the city’], the traditions [ kathestēkota] for sacrificing [ thusiā] to whom I will write down [ graphein] without writing down [ graphein] the reason [ aitiā] for [ epi+ dative] these [traditions]. Upon the altar [ bōmos] of Zeus Polieus they place barley mixed with wheat and leave it unguarded. The ox, which they keep already prepared for sacrifice [ thusiā], goes to the altar [ bōmos] and makes contact [ haptesthai] with the grain [ spermata]. One of the priests [ hiereis] they call the ox-slayer [ bouphonos], and he kills the ox; then, casting aside the axe [ pelekus] at that spot, according to the ritual [ nomos], he runs away. The others bring the axe [ pelekus] to trial [ dikē], as if they did not know the man who did [ drân] the deed [ ergon].