Subject: Laura/Madeleine Switcheroo
From: ethan@cicero.uchicago.edu (Ethan Ligon)
Date: 1990-08-27, 12:04
Newsgroups: alt.tv.twin-peaks

Seems pretty clear to me that Laura was having an incestuous relationship
with Leland P., wanted out, so murdered her look alike cousin, Madeleine,
and took her place.

This means, of course, that Madeleine is really Laura. Furthermore, 
Jacoby knows something about the switcheroo (or at least suspects); 
hence his willingness to go meet "Laura" (*Really* Laura), who others
suppose is Madeleine *posing* as Laura.  

This suggests that Laura shot Cooper.

Who killed Laura Palmer?  Nobody.