13 Steps Down - Ruth Rendell

At first I thought that this was a copycat murder mystery because it involved a man who was an avid fan of a former serial killer. Instead it turns out to be a a psychological foray into the mind frame of the same man who turns out to be a stalker of a celebrity. The reader has an inside loop on how he thinks, what motivates him, the lengths to which he will go, the scenarios that he concocts, etc. -- and when one thread of that carefully woven web unravels, things start to fall apart. The way the story develops and concludes is plausible, but for a thriller, the plot is a little too neat for my liking, though I did enjoy the book.