I'll go a ahead and say that the biggest found cluster consisted of over 200 accounts.
Now imagine someone comes to you with plausible data that indicate such clusters ? What would you have done ?
I'm pretty sure noone would have said "Well we said we wouldn't do another investigation. So no, let em have it".
Regarding the question of whom to contact - Just contact me. Prefferably only with questions but sure if you need to blow of some steam go ahead.
It's not what NEM did. But how they did it.
In silence. Anonymous. Not transparent. Bad timing etc.
Ofcourse it's good that a puppet with 200 accounts get deleted. But like I said; not the result, but the road to it is really wrong.