searchingforanswers, my condolences, I can´t really imagine how you must feel...
In Germany, the BFU - Büro für Unfalluntersuchung - Air Accident Investigation Bureau - is the competent that has to deal with the investigation of this horrible accident.
You will find their homepage/contact under:
BFU Bundesstelle für Flugunfalluntersuchung BFU - About us - BFU
There is nothing on the accident yet.
The investigation will most likely take years as you might already know. Even a interim report will not show up quick I think.
To the best of my knowledge (and business aviation is a fairly small group here) no new evidence has been found so far. I do fly a very similar aircraft, the Citation Sovereign (same cockpit basically) and I do know the airfield relatively well. If there are questions you wanna ask me, you are most welcome to do so per PN preferably (bear in mind I´m definately no expert in investigating air accidents, just a pilot...)