So apparently some CCC-connected hackers already unmasked one of them years ago (as reported in the update, which could have also just linked to the talk here: https://media.ccc.de/v/37c3-12134-hirne_hacken_hackback_edit... ) Makes you wonder if the investigators discovered this independently, or decided to maybe ask the hackers already involved in defending against them for help...
I'm not deep into the topic, but AFAIK there generally isn't a warm connection between the CCC and the BND in Germany (in the recent years mostly due to the BNDs involvement ins spying on German citizens, but I think there is also deeper history there). If a hacker collaborates with the BND they do run a risk of many of their peers not wanting to collaborate with them anymore.
Fun fact: In the 1990s, the CCC e.V. was declared a terrorist organization by the BND. Also, a lot of members have been sued for Landesverrat (high treason) for disclosing found vulnerabilities and/or doing journalistic work.
For example, the netzpolitik guys have been sued for high treason twice.
Just as a side note on how competent the German state is to use their existing talent to work on issues in cyber security.
> If a hacker collaborates with the BND they do run a risk of many of their peers not wanting to collaborate with them anymore.
Another fun fact: There is no effective witness protection program in Germany. You have to have been attacked almost murdered twice (with legal cases leading to prosecution) before you can apply for the witness protection program.
And they're asking themselves why all the witnesses in high profile cases from Europol/Interpol keep disappearing ...