Deuteronomy 19:4-6

19:4 Now this is the law pertaining to one who flees there in order to live, if he has accidentally killed another without hating him at the time of the accident. 19:5 Suppose he goes with someone else to the forest to cut wood and when he raises the ax to cut the tree, the ax head flies loose from the handle and strikes his fellow worker so hard that he dies. The person responsible may then flee to one of these cities to save himself. 19:6 Otherwise the blood avenger will chase after the killer in the heat of his anger, eventually overtake him, and kill him, though this is not a capital case since he did not hate him at the time of the accident.

Deuteronomy 19:11

19:11 However, suppose a person hates someone else and stalks him, attacks him, kills him, and then flees to one of these cities.