The head of my degree course (and the school overall IIRC) who i had for a few lectures always seemed a bit of a wrong'un, but mostly in the sort of basement dweller VL type of way, everyone openly made jokes about him being a bit of a manchild and there perhaps being something a bit off about him, but nothing too sinister. Then out of the blue in the middle of a semester a few years ago, a number of serious allegations were made against him, for which he was eventually found guilty. It was a bit of a strange period as massive chunk of our course material was written and taught by him, was always a bit awkward when the tutors would pull up a set of slides/documents with his name plastered all over them.