Witches’ Cache

From: Lewis Capuchin
Description: There are many suspects, but hardly any of them would bother with the hoax. However, while we were looking for the amulet, I saw an owl feather sticking out of this box. Is it related to the witch masquerade? The box is locked, lend me some tools to open it.
Completed: The lock of the triangular box slowly gives in... Done! Look, there’s not only owl feathers inside, but also pins like those stuck in the straw doll, and even a spool of red thread! Who left this box here? Wait, there’s a note at the bottom.