“Ius Naturale” is the law applicable to men in a state of nature. It precedes religions and kings both in time and in authority. “Ius Naturale” does not derive directly from the will of God. As Hugo Grotius pointed out in the early seventeenth century, even if there was no God, or if God was unreasonable or evil, natural law would still have moral force, and men would still spontaneously back it with physical force. God could not create men as they are, and at the same time make natural law other than what it is. A God that claimed to do that would be a mere tyrant, unworthy of worship.
The two major justifications given for original property, or the homestead principle , are effort and scarcity . John Locke emphasized effort, "mixing your labor"  with an object, or clearing and cultivating virgin land. Benjamin Tucker preferred to look at the telos of property, . What is the purpose of property? His answer: to solve the scarcity problem. Only when items are relatively scarce with respect to people's desires do they become property.  For example, hunter-gatherers did not consider land to be property, since there was no shortage of land. Agrarian societies later made arable land property, as it was scarce. For something to be economically scarce it must necessarily have the exclusivity property —that use by one person excludes others from using it. These two justifications lead to different conclusions on what can be property. Intellectual property —incorporeal things like ideas, plans, orderings and arrangements (musical compositions, novels, computer programs)—are generally considered valid property to those who support an effort justification, but invalid to those who support a scarcity justification, since the things don't have the exclusivity property (however, those who support a scarcity justification may still support other "intellectual property" laws such as Copyright , as long as these are a subject of contract instead of government arbitration). Thus even ardent propertarians may disagree about IP.  By either standard, one's body is one's property.
The matter is, government isn’t an individual organism that has some kind of higher understanding of our reality. No, it consists of separate people who try to work together; and as it is often the case when people work in groups, they generally work less effectively than individuals do, so, of course, there are mistakes, and even more than one can imagine. And with the execution being an irreversible action, there is completely no logical reason for such an action being based on insufficient data – and there is no data sufficient to legitimize death.