Belatedly (real life intervened)...
Morgana- Yes, as far as Clark knows it could be just about anyone. Bureau 39 again, Luthor... heck, even Lois. She is an investigative reporter after all, and by now she knows he's hiding *something*.
MikeM- Well, I'm glad you liked the second chapter better than the first! And I agree with you, Lois is much too smart to be taken in by Luthor. It never sat right with me that she went from wanting to get the definitive interview with Luthor to dating him, or that she only ever saw the apparent 'good' in him. She's supposed to be the cynical one, and yet she took Luthor at face value.
VirginiaR- Yeah, Clark is stuck between a rock and a hard place. Enlisting someone else's help to figure out who's bugging him puts his secret at risk, but so does not figuring it out. It's a bit of a catch-22.