Numbers 35:25-28

25The assembly must protect the manslayer from the avenger of blood. The assembly should send him back to the city of refuge to which he had fled and he is to remain there until the death of the kohen gadol who was anointed with the holy oil.

26“But if the manslayer should go outside the city limit of his city of refuge to which he had fled,

27and should the blood avenger find him outside the city limits of the refuge city, the blood avenger may put him to death without being guilty of his blood.

28The manslayer must stay within the limits of his city of refuge until the kohen gadol dies, and after the death of the kohen gadol , the manslayer may return to his property.