You do realize in Islam it states if you kill the life of one it is as if they killed the lives of all humanity.

Furthermore Shariah law (Which a lot of you have slandered off in the past few pages in regards to some of its rules) states that you should follow the law of the land, which the terrorist clearly didn't do as he commited murder which is clearly illegal.

Edit: Sorry I posted my opinion, even though I don't have " PhDs in Tafsir, Hadith, Tawhid, and Fiqh" so don't give it any credit.