IT MAY BE A HOAX, but social media is "reporting" that the perps are Bashr al-Taweed and Hassan Matti, two Syrian refugees who arrived a week ago. As of now, I can't find ANY official confirmation. So maybe it's true, or maybe someone just made it up.
But by applying Coulter's Law, the longer it takes to identify the suspects, the more likely it is that they aren't Caucasians.