What about this in general:
https://en.wikipedia.org/wiki/Northern_Ireland_peace_process
And this particular case: https://en.wikipedia.org/wiki/Martin_McGuinness
And this particular case: https://en.wikipedia.org/wiki/Martin_McGuinness
The Good Friday Agreement was signed before the Rome Statutes on War Crimes came into effect (in no small part as a response to similar "blank-slate" deals in the 80's and early 90's). That means that signatory countries are bound by international law to prosecute and punish war crimes and crimes against humanity committed after their signing, proportionally to the severity of the crime. That's what I mean by first-world justice. Even in Ireland, no crimes under the Rome statute after 2002 can be met with the level of impunity the FARC-Santos deal guarantees.
And with respect to McGuinness, even if the Rome statute had been in effect during his participation in the IRA, he was never charged with anything resembling a war crime, even after the Saville Inquiry. He would be more akin to a member of the shady, FARC-friendly political party "Marcha Patriotica". The crimes of the FARC leadership, on the other hand, are fully documented, and sentenced in-absentia. Most of them have over 400 years of cumulative sentences, including murder, extortion, torture, kidnapping, child recruitment etc. All constituting war crimes and crimes against humanity.
You asked for an example and I gave it to you a valid one. McGuinness was an IRA leader and IRA committed many kind of crimes; there are more ex-IRA leaders that are now in the civil life.
If I give you another example you will discard it for some random reason, so this discussion makes no sense.
On the other hand, if you see the signed peace treaties in the region, and in the world, you'll notice that these have generally gone well.
Bye.