Major spoilers below for the second half of Arrested Development Season 5, so be sure to watch before reading on.
Nearly six years after first introducing the mysterious disappearance of Liza Minelli's Lucille "2" Austero, Arrested Development was finally able to wrap that story up. Alas, because this is Arrested Development, not many neatly tied bows (or even a neatly tied Mis Trial sash) were utilized in the process, leaving the model home's door open for a host of conspiracy theories to creep around inside.
After laying it out for viewers that Lindsay and Lucille are actually half-sisters, and after showing us Michael's very first chicken dance(!!!), Arrested Development's Season 5 capper certainly appeared to reveal that Buster had been Lucille Austero's killer all along. However, the convoluted comedy almost did too good of a job setting up other characters' potential guilt, especially in these final eight episodes, making it harder to truly believe that Busty is wholly responsible. Let's run down the shortlist of not-so-ridiculous suspects, starting with Prince Motherboy himself.
Why He's Probably Guilty: Well, Buster DID confess in the final minutes of the episode. And just a few minutes prior was one of the best jokes of the season, when Buster metaphorically and literally put his hand-foot in his mouth by mistakenly thinking Lindsay was talking about Lucille 2 being pushed down the stairs, as opposed to Mimi.
It would be just like Arrested Development's creative team to put Buster through a murder trial while appearing innocent, only to pull the rug out in the end to show that he was guilty all along. It may not be the best subversion of open-ended true crime projects like Making a Murderer, since he'll likely just go back to jail, but the twist thematically fits.
Buster definitely stopped the disguised Tony Wonder from swinging that sledgehammer into Lucille's cemented body, so there's no question that Buster knew full well what, or who, was hidden inside. It can easily be assumed that Buster was inspired to hide Lucille 2 in the wall after dumping the cemented body for G.O.B., too.
Circumstantially, Buster is a self-confessed "monster" known for fits of barbarian strength and blind rage, and he'd rarely looked more upset on this series than when he confronted Lucille 2 at Cinco de Cuatro about juicing him up to keep him out of court. That she was banging "Oscar" didn't help. Plus, it was made very clear that young Buster definitely killed Mimi, and that he's got an M.O. for pushing older women down stairs. Remember when Buster was just a goofy doofus who liked giving massages?
Why He Could Be Innocent: Buster eventually confessed quite calmly while under the quiet duress of everyone else's expectations, which is usually when Buster resorts to predisposed behaviors, such as taking the blame for things and then talking about Mother. Viewers watched Buster being coerced into believing something once (even though it was the truth), so who's to say he hasn't been mentally guided to take the fall for Lucille 2's death?
Also, Buster's confession is merely "I did it," and not "I killed Lucille 2." As such, it can be proposed that Buster is merely confessing to putting Lucille Austero's masked body in the wall, and not to actually murdering her.
There still isn't any actually physical evidence pinning it to Buster, such as the missing video footage of him supposedly pushing her down the stairs. We mostly just saw memories of her laying on the stairs, so even if Buster did push her, that doesn't necessarily mean he killed her. After all, we saw Michael fall down the stairs after his chicken dance, and he wasn't that hurt. Granted, Lucille 2 is older and more fragile, but Arrested Development never really cemented how she actually died. (It's assumed an autopsy would take care of that.)
The body that fell from the cement didn't appear to be completely rotted or anything. (Maybe that's why she was so happy. Cabaret!) So unless she was only killed in the short time prior to being dumped into the cement, the body was likely being preserved elsewhere. Buster obviously could have stored the body before going to jail, and then picked it back up after being released, but where would he have kept it that no one else in this nosy family would have come upon it?
Many fans will likely also argue that the "Next Time On..." cappers at the ends of episodes aren't fully canon, due to certain instances in the past. If that was somehow a standardized rule in this universe, that would mean that Buster's confession and the corpse's discovery could be easily retconned. But since it isn't set in stone, or concrete, we'll still accept the events as reality.
Why He Could Be Guilty: As the main rival of the Bluth family and its company, Stan Sitwell makes sense as someone who would want to also take down the woman partly responsible for keeping the Bluths financially afloat. Especially if he was at any point fully enamored by Lucille Austero, who'd been fully enamored with Buster.
While Sitwell's head injuries could plausibly be the reason why he spontaneously decided to move out of his retirement community home after meeting Maeby's...family (and DeBrie), is it possible the wealthy developer actually needed to make a quick exit to avoid suspicion, or to find a new victim? After all, Tony Wonder reveals in the end that Sitwell is "missing," which his daughter Sally doesn't seem to be too worried about. Possibly because Sitwell is just hiding out until the heat dies down around Buster?
If this admittedly weaker theory had a smoking gun, it would be the map of the Spotted Palms property that Maeby came across in Sitwell's dresser. A bunch of different women's pictures were inside, with many of them X'd out, and a big circle drawn around Lucille 2's image. It's possible that he killed many of those women, maybe for their properties. He had made some pretty creepy comments about Maeby/Annette, also. I'm pretty sure one of them was about her smiling even when she slept. (Happiest corpse!)
Why He's Probably Innocent: To immediately counter the Spotted Palms map idea, Lucille is one of four women who's pictures aren't crossed out, but hers is the only one that's circled a bunch of times. So if he'd killed her, he probably would have drawn the X over her face by now. It's possible that these were just sexual adventures, or that he was attempting to buy their homes and got rejected, or some other situation that doesn't involve murder.
Plus, Maeby winked right into the camera right after that happened. If she wasn't making a sly nod to audiences that this was just a throwaway suspect gag, then why in the world would the character break the fourth wall like that in such a weird way?
Stan Sitwell probably does just have a head injury and is actually lost out there in the world, which is ultimately a more depressing outcome than if he was a murderer.
Why He's Probably Guilty: G.O.B. is the purest dilution of George Sr. and Lucille's worst personality traits, and there have been few evil schemes that the eldest Bluth brother has kept his hands out of. Especially the schemes that go terribly awry, which speaks to both of his cement-centered stage illusions. Sometimes, G.O.B. doesn't even have to know any of the details about what's happening in order to be complicit, and that speaks to him tasking Buster will dumping that "body," which was captured on the news.
G.O.B.'s storyline in Season 5 has been about his loving infatuation with Tony Wonder, coupled with him trying to understand his own sexuality, so it wouldn't make the most sense in the world for G.O.B. to have actively killed Lucille 2. However, she went missing after he got reverse-conned by Egg, er, Ann into having sex with Tony Wonder before then drugging Michael and allowing him to be used in a predator-catching reality show. So G.O.B. feasibly could have murdered Lucille without even blinking.
If G.O.B. had a normal-sized hand in this, it probably had something to do with the hiding and disposal of Lucille's body. Of all the characters on Arrested Development, the illusionist G.O.B. is most known for making things disappear – which was directly brought up by Gay Mafia leader Argyle Austero – and he's also known for all manner of narrative switcheroos. Let's also not forget that the egotistical shyster is also always just a Forget-Me-Now away from forgetting his own wickedness.
One of the most curious moments comes in the finale when the family starts speculating about Lucille 2, and G.O.B. whispers, "Remember who's in your corner," to Buster after everyone pretends they don't suspect Buster for Lucille 2's absence. That likely wasn't just positive sibling affirmation, either, but was further playing up the magician-and-assistant relationship they share, in which Buster is forbidden from sharing how tricks are done, with this season's resolution assumedly included in that list. Even though it was followed by G.O.B. blatantly revealing a trick's secret.
Why He Could Be Innocent: As implied above, G.O.B. usually isn't meticulous or thoughtful enough to mastermind any of Arrested Development's grand plots, least of all something that would go on for several months while also including a big court case. Barring miracles, there's likely no way G.O.B. could get away with murder without blowing it a hundred times over.
G.O.B. was one of the few characters on this show that hadn't borrowed a ton of money from Lucille 2, and thus didn't have any debt-stained motivations on that front like Michael or even Argyle did. Lucille 2 also hadn't made any threats to G.O.B.'s direct future, as she'd done with Lindsay, Tobias, Maeby and others.
Why He's Probably Guilty: Because this is Arrested Development, Argyle Austero became an automatic suspect just by being Lucille 2's younger brother. Which assumes that they're actually siblings, and that the Austero family isn't also just one big dark underbelly. And if they are that, he becomes even more suspicious.
Season 4 set up that Argyle got into his own financial situation with Lucille 2 when helping Tobias fund the (doctor) doomed Fantastic 4: An Action Musical production. If he's making those kinds of terrible money-burning decisions, he probably felt a lot of envy over the years regarding his sister's wealth and success.
Argyle is an opportunist that opens whatever business happens to fit his current needs, from party planning to drug rehab, and the specificity of his Austero Enterprises outfit ALSO having a "stone and cement" division cannot be a coincidence when it comes to the Lucille 2 reveal. It's possible he just wanted to get in on that wall-building money, but he's clearly the kind of person who finds reasons to hide things in building structures. It's called the Gay Mafia for a reason.
Trying to kill off Tony Wonder for pretending to be gay is certainly the act of a villainous criminal, and it's not like any of Argyle's scenes made him out to be the best brother imaginable to Lucille 2. He made threats on her behalf, but that's not proof that he wouldn't kill her. Argyle isn't ever exactly worried about her whereabouts, either, in the same way that Sally Sitwell wasn't in peril over her father being missing.
Having a sister at any level of government would possibly threaten to uncover Argyle's criminal acts, too, so Lucille 2's Congressional campaign likely caused some worries in her brother's camp. And because he couldn't very well trust her Bluth-aligned opponents to thwart her chances of winning the election, he might have needed to take a more personal approach to stopping her ascent.
Why He Could Be Innocent: Like lots of other bits in Season 5, it's highly possible that Argyle's presence was just a highly fashionable red herring meant to throw viewers off of the trail heading straight for Buster's next arrest. In that sense, he doesn't really have a lot of other obvious reasons why he'd be innocent beyond being her brother.
Why She's Definitely Guilty In General: While Lucille Bluth may not have physically pushed Lucille Austero down any stairs, or into a pool of cement, or anything else of that nature, the matriarch is as responsible for the majority of her family's emotional and mental issues (while George Sr. [beep]ed everything else up). So no matter what roles Buster and/or G.O.B. and/or Michael had in Lucille 2's death, Lucille is a big reason why they all ended up at positions in life where they would feasibly be guilty of murdering a longtime family friend.
Also, I would be higher on the belief that Lucille had a hand in sealing Lucille 2's fate, as it were, if she hadn't admitted to arranging the protesters at the Fakeblock/border wall event in order to bring Lucille Austero out of hiding. Remember how convinced she was in the past that Lucille 2 wasn't actually dead? Was that really all tied to George Michael and Maeby being misidentified while driving the stair car, or did she actually know something that others didn't?
I think one of the creepiest outcomes would be if Lucille had indeed known of Lucille 2 taking a self-imposed vacation after Cinco de Cuatro, only for her to get killed in some later incident that the show didn't address at all. Or maybe Lucille just fell down the stairs herself in the midst of a vertigo episode.
It doesn't seem like Arrested Development will be getting a Season 6, considering much of what's happened in the past, so it's very likely that this finale was the very last thing we'll see from the Bluth family. Personally, I think Michael and George Michael got away easy by just hauling ass in the stair car without saying goodbye. (Jason Bateman and Michael Cera were reportedly unable to film the rest of the finale's last scenes.)
Let us know who you guys think was responsible for killing Lucille Austero below, and don't forget you can now watch all five seasons in their entirety on Netflix.