Vixen
Penultimate Amazing
Only the truly sick would attack a country who is at war with no one and accepts refugees from around the world.
Sweden has had ongoing problems with migrant clashes and the far right neo-nazi groups over the past few years. Synagogues have been targeted, so it is not all to do with immigrants, as the Jews have been there for decades. Once refugees themselves, now a target for the extremists.
Of course that is no explanation or excuse for this truly heinous and barbaric act by this evil coward.