Both feature main characters named Charlotte who go by boy-name nicknames (Charlotte "Charlie" Newton in SoaD, and Charlotte "Chuck" Charles in PD).
Both deal with death and murder as subject matters.
And Macdonald Carey looks more than just a little bit like Lee Pace, only with bigger ears. Of course, if I work up the effort to do a screen grab and it turns out nobody else thinks he looks anything like Lee Pace, my whole theory is shot to hell.
Danged youtube for having a clip of the movie so I can't claim laziness as an excuse!
Well, here's a picture. Remember, I said "more than just a little," not "exactly totally without a doubt!" and I did say bigger ears:
Come on, just a little, right? Come on! Okay, whatever.
This sticker is dangerous and inconvenient but I do love Fig Newtons