[YEAH. . . probably. these kids, taking everything they get as a hint or code of some kind. but what else do they have to go on, now that the Deputy is dead, now that Shinnosuke is dead as well? Milla is certainly grasping at everything she can]

If we are under some sort of time limit, then why on Earth would the Sheriff not tell us that in the beginning? It seems like vital information, something we could learn without using up our merit.