Did no-one read the links "The motive for the attack is very fuzzy ... but no words of religious connotation were spoken."?
Of course, further details may emerge later but people are jumping the gun a bit
But who says it's because they were scantily dressed. The examining magistrate, who's at the scene and has, presumably, questioned witnesses says that it's not clear what the motive for the attack is but you, hundreds of miles away, assume that it's because the victims were scantily dressed.
As I said, further details may emerge later but no-one at the moment knows what the motives were
Has already been mentioned on BBC news reports, so maybe things are emerging.............again.