Unless you have a very weird legal code, I think that you will find that the perpetrators of any "torture" that happened in these "secret locations" are indeed in a "criminal prosecution scenario."
The US legal system has little, if any, jurisdiction outside of US territory. If the "perpetrators" were in the military, then UCMJ (Uniform Code of Military Justice) applies. If they were civilians, then things get mighty murky legal wise. Of course local law applies as does international law. Who's going to enforce the local laws and/or international laws that apply here?