Numbers 35:30
Whoever kills any person, the murderer shall be put to death by the mouth of witnesses: but one witness shall not testify against any person to cause him to die.
Torrey's Topical Textbook—AKJV

Deuteronomy 19:11,15
But if any man hate his neighbor, and lie in wait for him, and rise up against him, and smite him mortally that he die, and flees into one of these cities:
Torrey's Topical Textbook—AKJV