There’s something more subtle going on here. In order for the German police to identify and locate this person, someone from the migrant community must have fingered him.
I suspect that this “betrayal” is OK with the Muslim hierarchy in that it plays the German authorities and makes it look like the Muslim community is being cooperative. Thus, the Merkels of the world feel like the “problem” is only skin deep and also feel justified in coddling this community, in general. After all, they helped locate these fiendish, radicalized miscreants in their midst!
I heard a news item on the radio which said the found the number for this new suspect stored in Amri's cellphone.