“rounding people up for interrogation in dank rooms”
The people who did not “volunteer” will get coercive visits from LEO, to see if “eventually they will cooperate”.
How do you know? How do you explain to a judge that declining an invitation makes someone guilty? Unless the judge sucks then he/she cannot grant a warrant based on that. If the judge does then we have a bigger problem, aka a corrupt judiciary. On the other hand, if one of the people who doesn’t cooperate with the investigation happened to know the kids then that’s a red flag, no? Maybe there was some issue with the girls or a member of their family?
Means, motive and opportunity. Without all 3 it’s hard to convict someone of a crime.