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.

if he really has 200 stakes he should be kicked for sure
200 stakes really... come on, such suspicious conglomerations of stakes can destroy a project (i mean BTT registrations and not in the NXT-AE accumulated).