Numbers 35:27

and 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 .

and the avenger of blood finds them outside the city, the avenger of blood may kill the accused without being guilty of murder.

And the revenger of blood find him without the borders of the city of his refuge, and the revenger of blood kill the slayer; he shall not be guilty of blood :