The premise of the Code, and of Dexter's life, was that the only victims that wound up on his table and into the Gulf Stream were those who were missed by legitimate law enforcement.
Thanks for bringing that up, I remember thinking that when this all started. Think the writers have been a little sloppy with the code in general; guess it can be passed off as Dexter being confused/learning/etc., but has just never clicked with me as 'Dexter-like'.

















