This is wrong in the sight of Allah. A muslim cannot go around killing non muslims just like that.
However interesting enough. the article does not give any support to link the killing with the pope's foolish speech.
The only thing that was given was the fact that there was a speech condemning it some time before
and the SPECULATION of witnesses,
But Allah knows best what actually transpired.
More facts must be given before a proper detemination is made