Except the attackers haven’t been Arab.
No, but they sure have been radical Islamic terrorists!
They’re Nigerians. They could very well be Nigerian Arabs. For example...
http://www.prayway.com/unreached/peoplegroups2/1752.html
http://www.joshuaproject.net/peopctry.php?rog3=NI&rop3=108972
Shuwa Arabs are a sizable percentage of the Nigerian population.
Do I know if either are? No, but neither do you, and they certainly could be.
Either way, they’re Mohammedans.