Ok, so she went to join ISIS based on the ideals that they "promised" her, lets assume. However from the way the story reads, she left their camp and is now living in a refugee camp. What terrorist act would you prosecute her for?
I think that whatever the government does in this case, they're going to do something wrong in people's eyes. If they bring her back, they're going to anger the "let her rot, she made her bed" etc etc. However if they don't, they're going to anger the people who believe that they should be compassionate. Unfortunately there's no right answer here.