The Book of Astaroth

What if a Teaching Assistant witnessed a murder in the university cafeteria? What if he were preparing the last session for a class in the Experimental College that dealt with shamans and witchcraft? What if the murderer read the same book the T.A. is going to use for his X-college class? What if the T.A. asked an art student to make an illustration of Astaroth, a demon from the book the T.A. was going to use during his final X-college class? What if the art student hanged himself in the venue the T.A. was going to use for his last X-college class? What if Astaroth's words became a refrain in the T.A.'s consciousness?