Numbers 35:26-32
English Standard Version
Chapter 35
26But if the manslayer shall at any time go beyond the boundaries of his city of refuge to which he fled, 27and the avenger of blood finds him outside the boundaries of his city of refuge, and the avenger of blood kills the manslayer, he shall not be guilty of blood. 28For he must remain in his city of refuge until the death of the high priest, but after the death of the high priest the manslayer may return to the land of his possession. 29And these things shall be for a statute and rule for you throughout your generations in all your dwelling places.
30"If anyone kills a person, the murderer shall be put to death on the evidence of witnesses. But no person shall be put to death on the testimony of one witness.
31Moreover, you shall accept no ransom for the life of a murderer, who is guilty of death, but he shall be put to death.
32And you shall accept no ransom for him who has fled to his city of refuge, that he may return to dwell in the land before the death of the high priest.