SarahC:

There's not a one-to-one relationship between horribleness and attractiveness to women -- you never hear about women being hot for Jeffrey Dahmer.

Not a one-to-one relationship, to be sure, but stories like this strongly suggest some positive statistical relation: "No shortage of women who dream of snaring a husband on Death Row: experts ponder why deadliest criminals get so many proposals." The article references an academic book that dedicates a chapter to the phenomenon.

Jeffrey Dahmer might have been a bit too creepy even for the serial killer groupie population, but I wouldn't be surprised if he got an occasional love letter too.