Numbers 35:16-19

16But if he smote him with an instrument of iron, so that he died, he is a murderer: the murderer shall surely be put to death. 17And if he smote him with a stone in the hand, whereby a man may die, and he died, he is a murderer: the murderer shall surely be put to death. 18Or if he smote him with a weapon of wood in the hand, whereby a man may die, and he died, he is a murderer: the murderer shall surely be put to death. 19The avenger of blood shall himself put the murderer to death: when he meeteth him, he shall put him to death.