Description
It is possible these individuals acted alone, but it is far too common that Endless Court membership becomes a family affair. Seek out any living relatives of these three.
Interrogate them, and see if they break. If not, use this device to verify their claim of innocence. If they've joined the cult, they will have an aura of Regulos's power. If they are innocent, nothing will be revealed.
Upon completion
You've done a good job rooting out some footsoldiers. But we need to find some leaders.