I agree -- Hartley's only "famous" to that rather small segment of the viewing audience that watched Smallville
. I wouldn't say he's more famous than Hilarie Burton (who's currently a regular on White Collar
) or Nana Visitor. So it wasn't a given that he'd be the killer.
However, I did figure out he was the killer as soon as it was revealed that the dog was reacting to the poppy-seed perfume. I remembered that he was sitting next to Kay when she sprayed the fragrance. (Although, granted, I remembered that because I recognized Hartley from Smallville
They were having fun with the character names here -- Kay Capuccio (Ca-Pooch
-io) and Dr. Barker