If anyone believes that things like this happen only in Europe is wrong. Take America for instance. Every year we have several stabbing-incidents.
And those will continue until the IS won't be completely annihilated.
Not Europe's fault. And btw one question to every ignorant person who believes it's europes fault because they let them in: What are we supposed to do? an immigrant escapes into our country, what should we do with him?
Killing him would result in protests and medias would freak out like never before. Of course you also have the option of rejecting him... and what next? The country where he comes from doesn't want him... and what now? What should we do with him? Thats why we let so many people in our countries... and most of the time it helped the economy. Sure incidents like this happen but still even if we wouldn't let them in, it wouldn't get any better. Believe me. And to everyone: please just wait, because we will solve this somehow. Were not there yet, but we will.
EU pays turkey a Ton of money and will probably pay even more Asian countries so they accept those refugees. So, please, just give it 2 or 3 years and everything is going to be okay. We would have 100,000 refugees a month but because we pay them that money we only have about 1000-2000. And this number will decrease if people will believe in it. IS is also almost down, so we can only hope for bright future.