Canadyjd, Genesis 9 says "whoso" which can only refer to a person.
Genesis 9:6 (KJV) Whoso sheddeth man's blood, by man shall his blood be shed: for in the image of God made he man.
This verse is a series of "last-minute" instructions given to Noah at the end of the flood. It is assumes correctly that there will soon be governments. I said that the law given to Noah predated the Law of Moses when someone suggested that we should then have to obey the Law of Moses and therefore this early pre-Mosaic commandment had nothing to do with the Law of Moses. I think Matthew Henry gives the traditional Protestant commentary on what God meant.
Matthew Henry (1662 to 1714) does not support your viewpoint and does enunciate in detail the traditional viewpoint of Genesis 9:6, several verses calling for the execution of murderers. My point is that everyone is saying that prison is worse than execution but in the Arias case she begged not to be put to death so murderers such as her seem to fear execution more than life in prison. So they people who call for prison as worse do not seem to have any confirmation from the people being sentenced. Here is Matthew Henry's comment on Genesis 9:6:
"4. Wilful murderers must be put to death. This is the sin which is here designed to be restrained by the terror of punishment (1.) God will punish murderers: At the hand of every man’s brother will I require the life of man, that is, “I will avenge the blood of the murdered upon the murderer.” 2 Chr. 24:22. When God requires the life of a man at the hand of him that took it away unjustly, the murderer cannot render that, and therefore must render his own in lieu of it, which is the only way left of making restitution. Note, The righteous God will certainly make inquisition for blood, though men cannot or do not. One time or other, in this world or in the next, he will both discover concealed murders, which are hidden from man’s eye, and punish avowed and justified murders, which are too great for man’s hand. (2.) The magistrate must punish murderers (v. 6): Whoso sheddeth man’s blood, whether upon a sudden provocation or having premeditated it (for rash anger is heart-murder as well as malice prepense, Mt. 5:21, 22), by man shall his blood be shed, that is, by the magistrate, or whoever is appointed or allowed to be the avenger of blood. There are those who are ministers of God for this purpose, to be a protection to the innocent, by being a terror to the malicious and evildoers, and they must not bear the sword in vain, Rom. 13:4. Before the flood, as it should seem by the story of Cain, God took the punishment of murder into his own hands; but now he committed this judgment to men, to masters of families at first, and afterwards to the heads of countries, who ought to be faithful to the trust reposed in them. Note, Wilful murder ought always to be punished with death. It is a sin which the Lord would not pardon in a prince (2 Kings 24:3, 4), and which therefore a prince should not pardon in a subject. To this law there is a reason annexed: For in the image of God made he man at first. Man is a creature dear to his Creator, and therefore ought to be so to us. God put honour upon him, let not us then put contempt upon him. Such remains of God’s image are still even upon fallen man as that he who unjustly kills a man defaces the image of God and does dishonour to him. When God allowed men to kill their beasts, yet he forbade them to kill their slaves; for these are of a much more noble and excellent nature, not only God’s creatures, but his image, Jam. 3:9. All men have something of the image of God upon them; but magistrates have, besides, the image of his power, and the saints the image of his holiness, and therefore those who shed the blood of princes or saints incur a double guilt."
