Numbers 35:28-30

BRG Bible

²⁸ Because he should have remained in the city of his refuge until the death of the high priest: but after the death of the high priest the slayer shall return into the land of his possession.

²⁹ So these things shall be for a statute of judgment unto you throughout your generations in all your dwellings.

³⁰ Whoso killeth any person, the murderer shall be put to death by the mouth of witnesses: but one witness shall not testify against any person to cause him to die.