Five years after ISIS was defeated in Iraq, many Iraqi families of ISIS victims have still not found justice through legal means and turned to private investigators and assassins for help instead.
What a great story! Have you optioned the movie rights? I've never read a murder story where Im so completely on the side of the murderers (including the contract murderers, who know in advance how much extra its going to cost to bribe their way out the murder). Corruption so is pervasive in these countries that all the judges work off the same bribery price list, apparently.
Everyone learns in law school that the Rule of Law is preferable to this sort of thing, which indeed seems to flourish in the absence of a functional judicial system. On the other hand, the system you describe doesn't seem all that bad to me, as far as the fate of the underlying ISIS criminals is concerned. Justice is justice.