I put this item in one of the locked foot lockers in the basement in the cult barrack’s section.
I didn’t write anything down to show my players for this one, but simply described it as a list of names, descriptions of people, and details of some sort of ceremony.
In other words, this is a logbook of the cult’s victims kept by one of the head cultists. There’s a column for names of their victims. A second column with the victim’s physical description. And a third column telling gruesome details like, “Struggled profusely” and “No tranquilizers given this time.”