Warning: Major Spoilers Ahead for Only Murders in the Building
The big question at the end of Only Murders in the Building's first season is: who on earth killed Bunny? The show, which is a Hulu Original created by a returning Steve Martin and John Hoffman, follows the adventures of Charles-Haden Savage (Steve Martin), Oliver Putnam (Martin Short), and Mabel Mora (Selena Gomez) as they attempt to solve the murder of Tim Kono, a fellow resident of their upscale apartment complex, The Arconia. The trio publishes their findings as they go in the form of a podcast that shares its title with the show.
Like any good murder mystery, Only Murders in the Building features numerous fake-outs and twists. Every time the three think they have their suspect, whether it's the crazy cat guy Howard, Mabel's childhood friend Oscar, or even Arconia tenant Sting, the evidence points elsewhere. In a shocking last-minute twist, the real killer's identity in Only Murders in the Building ends up being Charles's girlfriend, Jan (Amy Ryan), who tries to poison him like she did Tim Kono. Fortunately, the trio is able to act quickly to save the building from Jan's plan to kill even more residents by piping toxic gas through the fireplace system.
With Jan in police custody, Charles, Oliver, and Mabel celebrate the success of their case and their podcast on the roof of the Arconia. But there's one last twist in store: when Mabel goes inside to get more champagne, Charles and Oliver both receive a mysterious text telling them to get out of the building. On their way to evacuate, they stop to collect Mabel and are shocked to find her kneeling over the body of Bunny, Arconia's housing board director, as set up by Cinda Canning (Tina Fey). She's been stabbed through the chest with one of Mabel's knitting needles. Despite Mabel's plea, "It's not what you think," the show's final scene has the three marched out of the building in handcuffs as suspected murderers. The good news for fans is that this cliffhanger ending means season 2's stakes will be even higher as Charles, Oliver, and Mabel try to clear their names of murder. And if Mabel is telling the truth that she didn't murder Bunny, it means there's another killer on the loose in the Arconia. While the killer could be someone not yet introduced, here's every known Only Murders character who might've had reason to do it.
Theo Dimas
Theo Dimas and his father, Teddy, are initially suspects in Tim Kono's murder because of their side hustle stealing jewelry from the dead, which Tim found out about before he died. As it turns out, neither of them killed Tim, but Theo was responsible for Zoe Cassidy's death ten years prior when he accidentally pushed her off the roof. Season 1 leaves the Dimases' fate somewhat unclear: they are exonerated of one crime but proven guilty of a few more. Even if they don't wind up in prison, Bunny would certainly have grounds to evict them. Could Theo have snuck back into the building to kill her in a fit of rage? Framing Mabel would be a bonus for him, too, since she helped prove his Only Murders in the Building guilt in the jewelry and Zoe Cassidy cases. Of course, depending on where the Dimases actually ended up after their arrest, it could be impossible for Theo to make it back to the Arconia.
Oscar's Father
Though he only appears in the show briefly, Oscar's father, Jose Torres, could have motive to murder Bunny, and especially to frame Mabel for it. As the Arconia's superintendent, he likely interacts with Bunny, the board director, pretty frequently. She's known for being bossy, gruff, and self-important, so it's not hard to imagine her driving Jose crazy with requests from the board. This alone might not be enough for him to want to kill her, but Jose (played by Anthony Ruiz, who appeared in Jon Bernthal's The Punisher) is also no fan of Mabel. When she shows up at his door in episode 3 looking for Oscar, he turns her away, not wanting his son to get dragged back into the mess that sent him to prison 10 years prior. Though Oscar's name has been legally cleared by the end of season 1, his reputation might take longer to catch up. If Jose is still harboring a grudge against Mabel for getting his son into trouble, he might want to see her spend some undeserved time behind bars as well.
One of the OMITB Super Fans
Episode 8 of the series features a group of fans obsessed with the Only Murders in the Building podcast. Sam, Paulette, Lester, and Grant camp outside the Arconia waiting desperately for a new episode to drop until Oliver invites them inside to see if they can help crack the case, which makes them very excited. But with Tim Kono's murder solved at the end of season 1, the future of the OMITB podcast is uncertain. It's possible that one of the fans, hungry for more true crime content, killed Bunny to keep the amateur sleuths in business. As Charles, Oliver, and Mabel are escorted by police out of the Arconia, they pass a line of on-lookers, one of whom is Paulette. While everyone else in the crowd looks shocked or angry, Paulette has an awe-struck smile on her face like she's eating it up. Even if she has nothing to do with Bunny's death, that's pretty suspicious.
Cinda Canning (Or Her Assistant Poppy)
Though they begin the show as strangers, Charles, Oliver, and Mabel bond over their shared love of true crime podcasts, especially those by the famed Cinda Canning. Episode 4 sees the trio consult Canning for advice, and she winds up boosting their popularity in Episode 6 by name-dropping their podcast on The Tonight Show. Though Canning isn't outright dismissive of the amateur podcasters, she clearly doesn't perceive them as a threat to her within the true crime industry. But with Only Murders in the Building gaining momentum by the end of the season, and a shocking revelation of the real killer to boot, Canning may now be looking at Charles, Oliver, and Mabel as competition. Killing Bunny would kill two birds with one stone by getting the three out of her way and providing new material for her own podcasts. It's also possible that Canning's assistant, Poppy, committed the Only Murders in the Building season 2 murder for the same reasons, with or without Canning's knowledge.
Mabel
It's no secret that Mabel isn't a fan of Bunny. The board director campaigns against the OMITB trio throughout the series, and in her last conversation with Mabel and Oliver she threatens, "I'll get you gone sooner or later," to which Mabel replies "Hey Bunny, congrats. You're the most hated person in the building now, you cranky old b**ch." It's possible that Mabel would want Bunny gone before she could make good on her word and evict one of the gang.
It's also possible that Mabel killed Bunny by accident. The murder weapon was a knitting needle, which Mabel carries on her whenever she goes out in case she needs to stab a stalker or would-be assailant. Could Bunny simply have entered the apartment at a bad time, startled Mabel, and triggered a self-defense reflex? If so, it wouldn't leave Only Murders in the Building season 2 much mystery to solve, but the knitting needle certainly seems to point to Mabel in one way or another.
Sting
No theories about Only Murders in the Building would be complete without considering Sting as a murder suspect. Episode 4 of the first season sees the trio investigating the singer because Tim Kono used to work for him and lost quite a bit of his money, but they quickly learn that while Sting was furious with Tim, he wasn't the one who killed him. Sting doesn't appear in person after this episode because he's on tour, so he might still be out of town when Bunny is killed, giving him an alibi. But if Sting did kill the board director, it could have something to do with his apartment renovations. Did Bunny slap him with fees and restrictions bothersome enough to commit murder? Whether or not Sting is the culprit this time, it would be fun to see him return. With Only Murders in the Building renewed for season 2, plenty of theories about who killed Bunny will be on the table.