Final answer:
Antonio Nunez was sentenced to imprisonment until death because he was found guilty of a crime that carried the death penalty as its punishment.
Step-by-step explanation:
Antonio Nunez was sentenced to imprisonment until death because he was found guilty of a crime that carried the death penalty as its punishment. The specific details of the crime and the conviction are not provided in the question, so it is not possible to give a more specific answer. It is important to note that sentencing to death requires a thorough legal process and is typically reserved for the most serious offenses.