At couples' therapy, Rita weepily plows through half a box of Kleenex, while Dexter sits there nonplussed by all these weird emotions. Is it at all strange that Dexter hasn't tried to fake emotions of remorse, regret, and intimacy with Rita over these last couple episodes? Hadn't he gotten pretty good at imitating regular people? Whatever, I'll ignore those questions for the moment because I see their therapist is being played by Roma Maffia, a.k.a. Liz from Nip/Tuck! It's weird seeing her as a character who isn't being completely abused and humiliated. Dexter makes the mistake of thinking the apartment is the issue here, which leads Rita to be all, "See! See! He never listens and he's always up in his head, and whenever he speaks it's all lies." "Not...all lies," says Dexter, unexpectedly truthful. Rita brings up the dread specter of Lila, as if I wasn't already feeling hostile towards her, but Dr. Roma Maffia does interject that, given the Lila situation and the (supposed) drug addiction, she kind of knew Dexter was secretive before she married him. Can't go expecting men to change! She's got you there! Rita (sincerely) and Dexter (probably not sincerely) agree that they don't want to keep on making the same mistakes. Unless Dex can be completely honest with her, Rita doesn't want to stay together.
Back at work, Dexter's in that room where he bashes plaster skulls full of red goo in order to simulate spatter patterns. Which I've always been dubious of, to be honest. Wouldn't the blood pressure within a human head cause significant differences in spatter from a fake head with red corn syrup inside? I mean, whatever, it's a great and creepy visual, but it seems like shoddy police work. Anyway, so here's Dexter, cracking fake skulls like they're ostrich eggs, trying to see which kind of hammer Trinity used (they want to be able to track the purchase of the model number.) LaGuerta's getting impatient at Dexter's (intentional) slowness. What nobody expected, of course, was that Masuka would be having the week of his life. He shows up with a DNA report -- yes, that smudge Dexter found was cremated human remains (much like the ones we saw Trinity spread at the suicide-mom crime scene), including a bone fragment, and he was able to make out two strands of DNA, one from the remains, and one from the saliva used to get it to stick to the wall. Masuka's feeling it today. And not in the way he's usually feeling it. LaGuerta tells him to run it through their databases (though DVO says he's already checked and Arthur Mitchell isn't in any of the police databases).