Numbers 35:27-31

and the blood avenger finds him outside the border of his city of refuge, and the blood avenger kills him, he will not be guilty of bloodshed,

because he should have remained in his city of refuge until the death of the high priest. But after the death of the high priest the one who committed manslaughter may return to the land of his property.

‘These things shall be a statutory ordinance for you throughout your generations in all your dwelling places.

‘If anyone kills a person, the murderer shall be put to death on the testimony of witnesses, but no person shall be put to death on the testimony of only one witness.

Moreover, you shall not accept a ransom for the life of a murderer who is condemned to death, but he must be put to death.