Here's what happens with Louis:
Dexter's boat is found somewhere, no body.
The blood on the bottom of the boat is found, linked to Louis.
(Maybe Deb gets someone besides Dexter to do the blood work, since this is Dexter's boat his position may legally compromise him)
Dexter is a prime suspect when it's found out that Louis told his girlfriend that Dexter had framed him to lose his job at work... Deb is able to confirm this by remembering Dexter mailed the same package to Miami metro in the episode last. But she won't.
And then LaGuerta will call her on it because as everyone knows, she's just waiting for the right moment to smoke Deb out of Miami metro for good.
Dexter being outed as a killer will take all season. And I suspect that each of the main characters will find out, one by one. I think by next week Deb may end up being sympathetic to Dexter and will start to try and help him. I just can't imagine them fighting against each other. As Deb says repeatedly, Dexter is "all she has."
And maybe he'll only be outed as a killer to a small group, because I'm not sure what the writers could do with a final season of Dexter if everyone knows. A season long trial? Snooze. A season long stint on death row? Unlikely. Though I'm sure Dex would hold his own in prison.
I'm glad the show is finally going in a new direction. They could have done this much earlier. It's a miracle this show is still as fresh as it is.
My only complaint so far is (and others had commented about this last week) Dex should be letting Deb know about all the shit that went down with the Trinity Killer + Rita.
Killing off Rita was the best thing for this show!