Numbers 35:16-18

“But if he struck him down with an iron object, so that he died, he is a murderer. The murderer shall be put to death. And if he struck him down with a stone tool that could cause death, and he died, he is a murderer. The murderer shall be put to death. Or if he struck him down with a wooden tool that could cause death, and he died, he is a murderer. The murderer shall be put to death.