Numbers 35:24
35:24 then the community must judge between the slayer and the avenger of blood according to these decisions.
Deuteronomy 19:11-12
19:11 However, suppose a person hates someone else and stalks him, attacks him, kills him, and then flees to one of these cities.
19:12 The elders of his own city must send for him and remove him from there to deliver him over to the blood avenger to die.
Joshua 20:4-6
20:4 The one who committed manslaughter should escape to one of these cities, stand at the entrance of the city gate, and present his case to the leaders of that city. They should then bring him into the city, give him a place to stay, and let him live there.
20:5 When the avenger of blood comes after him, they must not hand over to him the one who committed manslaughter, for he accidentally killed his fellow man without premeditation.
20:6 He must remain in that city until his case is decided by the assembly and the high priest dies. Then the one who committed manslaughter may return home to the city from which he escaped.”