My money is on the Muslims...
The irony in all this is that "socialist Europe" intentionally loosened their immigration laws so they could create a larger worker-class to subsidize their social programs. Looking at the birth/death rates of the indigenous people compared to immigrants...especially Muslims, is freightening. They're digging their own grave and they don't even realize it.
Socialist Europe has to come to grips with an immigrant population that is set to overtake their countries. It will be interesting to watch how France and Sweden deal with their Muslim "problem".
Don't we have our OWN problems with the criminal invaders???