Fiction book about serial killer; a very intelligent "normal guy" who gets curious about what it would take to be a serial killer. He's actually a sane, married guy

[Hope]

I'm trying to remember the name of a fiction book about a serial killer that I read around 1998-1999. It was already "older" then, so I'm guessing it was written in the 80s or early 90s.

The plot involved a very intelligent "normal guy" who gets curious about what it would take to be a serial killer. He's actually a sane, married guy who begins killing people as an academic study, not necessarily for the thrill (though eventually he gets addicted to the thrill, too).

He first figures out that he has to make sure there is absolutely no connection to him, so he finds his first victims at truck stops if I remember correctly. Eventually he gets better and branches out.

I remember details about the plot twist at the end, too, but I won't post those here.

[Lobstergirl, au gratin]

You can reveal all the spoilers as long as they are not in your header.

[Hope]

SPOILER ALERT

At the end, his wife figures out what he is doing. As she finds clues and puts things together, she writes all her notes in a journal. He begins to suspect that she knows, and he stumbles upon her journal where she has recorded everything she is going to take to the police. At this point you think he is sure to kill her until....the author reveals that the journal is written in braille (because wife if blind) and he can't read it!