Females. Possibly perceived as less of a threat and able to move freely where obviously these people weren't here by legal means. It made sense to Grainne.

"So that's it... I think I understand." A small flash of pain crossed Grainne's face in remembrance of her own lost children. Not that she approved of the man's methods, but she could understand why one would be driven to measure like that over a child. "We'll need a general starting area to know where to look. It would be useful to pick up her trail where it starts," she glanced around at the hideout, "though I suppose that is out if she left from here."