I have traveled to quite a few places where I've encountered volunteers with Christian Peacemaker Teams. I've never been to Iraq, so that's not one of the places. But I can say this, which is what others have been saying since some of the CPTers (as they are known to anglophones) were abducted in Iraq last week. The CPTers might have the word 'Christian' in their name, but they are no missionaries. They might have 'peacemaker' in their name, but that isn't a euphemism for imperialism the way 'peacekeeping' or 'peacebuilding' can be. They are people of conscience who are very much anti-imperialist in the most important way - in their actions.
They should be released unharmed. Sign a petition here.