I am thinking they found notes, drawings, a notebook with sadistic fantasies or maybe listing some of the children who he "liked" or had caught his eye at the complex. Or perhaps a private journal outlining some things he got up to before coming to Canton, things no one was aware of so no criminal investigation.
This is in addition to possible DNA evidence and/or something belonging to Jorelys
I cannot help but think there is something on paper tho. Drawings, IDK, if you fantasize about doing something THIS depraved to a beautiful little child, you gotta be thinking about that for a while. Those thoughts had to have outlet somewhere, somehow.