Only Murders in the Building Season 3 ending explained: Who is the killer?

Lucy-Jo Finnighan
Martin Short, Steve Martin, and Selena Gomez in Only Murders in the Building Season 3

Only Murders in the Building Season 3 has drawn to a close – here’s what happened at the end, who’s the killer, and what it means for the next chapter.

The Only Murders in the Building Season 3 finale has aired on Disney+. The series follows three unlikely friends Charles, Oliver, and Mabel – played by Steve Martin, Martin Short, and Selena Gomez respectively – who live in the prestigious Arconia building, as they attempt to solve the mystery of their neighbors’ deaths, all while making a podcast about it.

The first two seasons of Only Murders have served many twists and turns, and both ended on cliffhangers with brand-new murders. Season 2 for example ended with famous actor Ben Glenroy – played by Paul Rudd – collapsing dead on the stage.

So., the core question of Season 3 has been: who killed him? Here we’ll be discussing his murder case, along with how else Season 3 of Only Murders in the Building ends, so before we get into it: major spoilers for Season 3 ahead!

Who killed Ben Glenroy in Only Murders in the Building Season 3?

It turns out the killing pair were a mother-and-son duo: Donna and Clifford Demeo. Donna attempts to poison Ben and Clifford pushes him down the elevator shaft.

Let’s discuss the messy details of Ben’s death. While Ben collapses onstage at the beginning of Season 3, and he does technically die for around an hour, he ends up popping back up right as rain. He even joins the cast party, and makes an ominous speech, explaining how his near death experience has pushed him to be a better person to those around him.

We now know that it was Donna Demeo, the producer of the show, who poisoned him. She did this by putting rat poison on a cookie and left it in Ben’s dressing room, which he later ate in a state of emotional vulnerability. Why did she do this? Well she wasn’t the only producer, as this was her son Clifford’s first stint. After reading a poor review of the play, which placed Ben as the main problem, Donna took action to try and save her son’s career, hence the murder of Ben. The fact that she is terminally ill also made her more reckless, and she is even willing to take the fall for Ben’s own fall.

See, while Ben comes back to life, he doesn’t get a chance at redemption, as his dead body later crashes through the ceiling of the Arconia’s elevator while our main trio are riding it. This is because he was pushed by Clifford, in an attempt to save both the show and his mother. In fact, Clifford admits that he never wanted Ben in the show to begin with, so when Ben realises his mother poisoned him, Clifford acts violently.

How does Only Murders in the Building Season 3 end?

At the end of Only Murders in the Building, both Donna and Clifford Demo are taken into custody, as both accept the deeds they’ve done, but still claim they were doing it just to protect the other.

As for other things that happen in the season finale, despite its many obstacles, Oliver’s show Death Rattle is well-received, with Oliver even taking centerstage for opening night. Not only that, he maintains his relationship with Loretta, scoring a happy ending.

As for our other leads, Charles is getting texts from Joy, and Mabel may be moving to LA with new love interest Tobert, which perhaps puts the future of the podcast up in the air.

But it appears that they may have one more case to cover. See, Charles’ stunt double Sazz Pataki (played by Jane Lynch), is wandering through Charles’ apartment when she suddenly gets shot by an unknown assailant. On death’s door, she begins to write a message on the ground in her blood, and the episode ends.

Seems like there’s a new murder in the building, but that’s for Season 4 to figure out.

Only Murders in the Building Seasons 1, 2 & 3 are currently available to stream on Disney+. Check out more of our Only Murders in the Building Season 3 coverage here.

About The Author

Lucy-Jo is a Movies and TV Writer at Dexerto, and has previously written for Screen Rant and Girls on Tops. After earning a Master's Degree in Film and Literature, Lucy-Jo now loves covering films, TV shows, and anime, especially if it's something by Mike Flanagan, or anything drenched in camp. You can contact her at