In relations to the crimes against humanity there is a ECHR ruling from 11th November 2012 in case 4455/10, Marguš vs. Croatia. Have a look. Conclusion is that there can be no amnesty in such cases.

Crimes against humanity should not be condoned. Let the court decide the outcome.

But, for exemple, in Brazil the court voted to maintain the amnesty law - even if Brazil is a signatory to international treaties for the promotion of human rights - ignoring international law. One of the best analysis about this "evil choice" was from Berber Bevenarge.

Such violations of international laws should be handled by the International Community. There are methods available in the UN system to check such violations. When it is crimes against humanity impunity can not be the order of the day. Eternal vigilance is another effective method.

Thank you for your responses. Much appreciated.

My personal experience with war criminals (I interviewed quite a few) is that apart from few exceptions, such as vey young kids, they never really regret what they have done: the power and the thrill are too great. A suspended amnesty (something like parole) might be a good idea in the case of the lowest actors, but certainly not for the middle ranking operators (the organizers, such as Eichman) or the top ones (the commanders, who are the originators of the genocidal idea, such as Heydrich or Hitler). German experience after the war is that many of the operators of the SS and Gestapo found quickly a similar job in the STASI (so did the SAVAK's lower officers in Iran, who continued to apply their skills for the Mollahs); and those who did not spent much time in secret networks to help their peers find refuge in Latin America or elsewhere.

With regard to young kids, it is known now (see the works of Berthoz on vicariancy) that there are in human beings 2 windows for the building of the capacity to empathize with others, around 7 and 14 years old. Unfortunately, we are doing close to nothing to help former LRA or Khmer Rouges of that age to reinsert into society, and even less to prevent the brutalization (see works by Audoiun-Rouzeau and Grossman in particular) by organizations such as the LRA, Hutu killers, Jamaat, ISIL, Hamas, Hezbollah or the PLO from endoctrinating a new generation of fighters.

An interesting tool developed in situ has been the gacaca in Rwanda, which rely on local supervision, on the basis of admission by the guilty party.

I have a lot of documentation on that topic, since I have been creating a new science, Juripragmatics: why and how people communicate in the hearing room, on the basis of my experience as a linguist, lawyer, justice administrator and judge in those fields.

2 addenda/corrections:

1- it is Audoin-Rouzeau, at U de Picardie, at http://cespra.ehess.fr/index.php?2146

and Grossman, at http://www.killology.com/bio.htm

2- a very recent example of the continuity of savagery is Izzat Ibrahim al Douri, VP of Iraq under Saddam, who is now allied with ISIL:

   - http://en.wikipedia.org/wiki/Izzat_Ibrahim_al-Douri

   - http://www.jeuneafrique.com/Article/JA2790p044.xml0/

   - http://www.france-irak-actualite.com/2014/03/r%C3%A9sistance-irakienne-izzat-ibrahim-al-douri-prend-la-parole.html

   - http://www.globalsecurity.org/military/world/iraq/al-douri.htm

Thank you dear colleagues.