Islam is evil beyond anything you can imagine:
Islam is a theocracy. It is not just a religion but rather it IS a combination of religion and government. That's why they are so adamant in passing Sharia Law wherever they may be. That is why they desire NOT only regional or territorial Caliphate, but out of necessity, they MUST acquire world wide caliphate.
These two men WERE/ARE enemy combatants and should be treated as such. In fact, one could make the case that because the younger was made a citizen, he is now allegedly guilty of HIGH Treason. Read him his rights. Who cares. But try him as an enemy combatant guilty of high treason. If found guilty; capital punishment.
He is Russian by rights of political geography.