Not practical. These people are war criminals.
They have engaged in slaughter of civilians and prisoners, both protected persons under the Geneva Conventions. According to the Conventions, all that need be done is that a "competant tribunal" (it says nothing about what constitutes such a tribunal) determine that they are war criminals and they are BEYOND THE PALE of international law. They are NOT COVERED. EXCLUDED. Essentially, they have no rights whatsoever.