MURDER. From the days of Noah the biblical penalty for murder was death; “Whoever sheds the blood of man, by man shall his blood be shed” (Gen.9.6). Throughout the OT times, the ancient Semitic custom of the avenger of blood was followed: a murdered man’s nearest relative (the goel) had the duty to pursue the murderer and kill him (Num.35.19). Since in the practice of avenging blood in this fashion men failed to distinguish between murder and manslaughter, and vicious blood feuds would frequently arise, the Mosaic Law provided for cities of refuge (Num.35.1-Num.35.34). To these cities a person pursued by the avenger of blood could flee. He would be admitted and tried; if judged guilty of murder, he would be turned over to the avenger; if judged innocent, he was afforded protection in this city from the avenger. It appears likely that the advent of the monarchy began a trend away from the ancient goel custom, for we find the king putting a murderer to death (1Kgs.2.34) and pardoning another (2Sam.14.6-2Sam.14.8).
In a murder trial, the agreeing testimony of at least two persons was necessary for conviction (Num.35.30; Deut.17.6). An animal known to be vicious had to be confined, and if it caused the death of anyone, it was destroyed and the owner held guilty of murder (Exod.21.29, Exod.21.31).
The right of asylum in a holy place was not granted a murderer; he was dragged away even from the horns of the altar (Exod.21.14; 1Kgs.2.28-1Kgs.2.34). No ransom could be accepted for a murderer (Num.35.21). When a murder had been committed and the killer could not be found, the people of the community nearest the place where the corpse was found were reckoned guilty. To clear them of guilt, the elders of that community would kill a heifer, wash their hands over it, state their innocence, and thus be judged clean (Deut.21.1-Deut.21.9).——JBG
International Standard Bible Encyclopedia (1915)
2. The Hebrew Law:
(a) child murder;
(b) parricide; or
(c) taking life by poison;
Frank E. Hirsch
Crimes and Punishments