As always, I like to look at these situations not as isolated incidents but as symptoms of much larger issues. The rise of the far-right, these killings and the rise of anti-immigration sentiments are merely the result of the EU's suicidal policies. Everyone with a minimum of knowledge knows you can perfectly achieve the same with natives as you can with immigrants, so there aren't special benefits immigrants bring to society - Moreover, someone who is at least a bit rational knows perfectly that importing immigrants with care and picking who you want (like qualifications, background, etc.) is wise and should be promoted - Importing culturally incompatible rednecks is not, and Sweden is merely seeing the consequences of importing so many immigrants, specially Muslims.
Whoever fights monsters should see to it that in the process he does not become a monster. And if you gaze long enough into an abyss, the abyss will gaze back into you