Adan was heard shouting Allahu Akbar! Arabic for Allah is Greatest! as he stabbed his victims.
I can see why the FBI is so confused about the motive. The MUSLIM TERRORIST did not actually explain to his victims why he was stabbing them. He only asked if they were Muslim right before he tried to kill them. It's not like we have ever seen anything like this before. It's just so different this time.
(Sarcasm)
The FBI also has the same problem with DemonRat terrorists, like the subhuman who almost murdered Steve Scalise and tried to murder as many Republican Congress,members,as he could get in his sights. Never found any terrorism there, regardless of the perpetrator’s own writings.