[@KatherinWinter]

I figure that if none of the kids have any strong taint or signs that they were possessed, and if the dogs can's pick up any consistent evidence of its presence elsewhere in the school (the slim traces they did find probably being from its dash out), then it's likely that it was called up and spent most of its time down there. I'm going to need to look for any sort of occult ritual: the remnants of a circle, symbols, pages from a book, stray blood. Anything ooky-spooky that Curwen would recognize. Also any signs that someone was trying to dispose of something.