Killing by accident.
Numbers 35:23 Or with any stone, wherewith a man may die, seeing him not, and cast it upon him, that he die, and was not his enemy, neither sought his harm:
Deuteronomy 19:5 As when a man goeth into the wood with his neighbour to hew wood, and his hand fetcheth a stroke with the axe to cut down the tree, and the head slippeth from the helve, and lighteth upon his neighbour, that he die; he shall flee unto one of those cities, and live:
The avenger of blood might slay those guilty of unjustifiable.
Numbers 35:19 The revenger of blood himself shall slay the murderer: when he meeteth him, he shall slay him.
Numbers 35:27 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:
Protection afforded in the cities of refuge to those guilty of unjustifiable.
Numbers 35:11 Then ye shall appoint you cities to be cities of refuge for you; that the slayer may flee thither, which killeth any person at unawares.
Numbers 35:15 These six cities shall be a refuge, both for the children of Israel, and for the stranger, and for the sojourner among them: that every one that killeth any person unawares may flee thither.