Exodus 21:13-14

13However, if he did not lie in wait [for him], but God allowed him to fall into his hand, then I will establish for you a place to which he may escape [for protection until duly tried].

14But if a man acts intentionally against another and kills him by [design through] treachery, you are to take him from My altar [to which he may have fled for protection], so that he may be put to death.