He Either Moses, as in the following clause, or some other person by his appointment; which may be the reason why he is not named here, as he is to the sprinkling of the blood, which was an action more proper to the priest, and more essential to the sacrifice.
Related Commentaries of Leviticus 8:19
Leviticus 8:19
19 And he killed it; and Moses sprinkled the blood upon the altar round about.