Actually who cares if it was one, two, or three? Islam, and Jihadist Imams, will easily prey on young, disturbed young men, and tell them they can get a full dance card, and Nirvana, by murdering some kafirs while shouting 'Yaba Daba Doo'! (or some close facsimile thereof).
Or it could be an organized cell of Islamic Terrorists. Who cares? Satan's lie of Islam is the root of this issue. And the Governments that import this pestilence into their countries are enemies of the people they are supposed to represent.
Spot on correct!