But what happens next has the potential to make him grow up in a hurry, as when Dexter answers a knock at the door, he finds LaGuerta, who with the aid of two uniforms arrests him on the spot for the murder of Hector Estrada. Jamie, who you'll remember was once LaGuerta's sister-in-law, tries to intervene, and after being thwarted by one of the unis, she goes to call Deb, leaving LaGuerta emotionally to read Dexter his rights. LaGuerta, it's your big moment, so how about not casting your eyes down every two seconds so it looks like you've got a Miranda cheat sheet written on your hand?
Cut to Dexter being perp-walked right into the MM work area, which seems perhaps a bit much, and obviously, everyone is like WTF? Batista makes a big show of confronting LaGuerta, and look, I have no problem with people generally exhibiting shock at this development, and Batista has always been a staunch ally of the Morgans. But I think the show missed an opportunity to involve Quinn in an interesting way, given that he was the only cop on the force besides Doakes who ever thought there was something weird about Dexter. Maybe they're holding back everyone's suspicion of Dexter until next season, but it does seem like he should be an early adopter.
Anyway, Deb's shocked when she sees what's going on, and even as Dexter gives his blandest, most unconcerned look, Deb tries to get Dexter released, to no avail. LaGuerta tells her in no uncertain terms that as family, she needs to recuse herself from involvement in this situation, and then walks off, but not without Batista hot on her heels.
In the interrogation room, LaGuerta confirms that Dexter's official statement is that he went fishing the night before and then went home to be with Harrison. Dexter tells her he didn't kill Estrada, so she asks if he didn't take his body, cut it into bags and throw it into the ocean? As Batista observes from inside the room and Deb from out, Dexter's like, still no on that, and why would I, so LaGuerta replies, because Estrada cut up your mother, and sometimes there's a symmetry in the way killers operate? Dexter's like, la la la, I brought ice on the boat because my cooler broke, and that's what was in the bags, and by the way, what phone are you using because that's pretty good resolution from your little impromptu stakeout. LaGuerta, however, heatedly informs him that she found in one of the bags a shirt with Estrada's blood on it, along with Estrada's wallet. But the mild scientific curiosity Dexter's exhibiting toward her suggests he's got an ace up his sleeve even as LaGuerta goes on that he framed Doakes after she defended Dexter to him, and he betrayed her and the Department.