The attack showed that no part of the country is immune to the potential for violence fueled by anti-immigrant hatred.
So, I have friends in Hanau. Two of them were in that Shisha (Hookah) Bar. He sent me voice messages telling me he was sitting in the smoking room as several men appeared and started the shooting.
It reminds me of the NSU case where several people were killed by allegedly three people (I think only the two men did the shooting, the woman was only supporting their actions).
The German defense of the Constitution was apparently involved in the NSU case, there are tons of evident. The only issue is that their official documents are closed for 120 years until people can ask to view them:
Considering these facts and what they told me, I can imagine that the defense of the Constitution is involved.