Numbers 35:17-19

17And if he struck him with a stone in the hand, by which he would die, and as a result he did die, he is a murderer; the murderer 1must be put to death.

18Or if he struck him with a wooden object in the hand, by which he would die, and as a result he did die, he is a murderer; the murderer must be put to death.

19The blood avenger himself shall put the murderer to death; he himself shall put him to death when he meets him.