Rex Bailey is the protege of Sazz Pataki in Only Murders in The Building. He goes by the alias Marshall and also writes the screenplay for the film version of The Only Murders in the Building.
Episode 9 of Season 4 titled “Escape from Planet Klongo” gives us an important clue that confirms Rex Bailey is the protégé.
Charles, Oliver and Mabel initially thought that Glen Stubbins was Sazz Pataki's protégé. But, they met a bartender outside the hospital where they confronted Glen about killing Sazz. The bartender then explained to them that he was not Sazz's protégé. Only three people in the world knew who he was, Glen, Sazz himself, and film director Ron Howard.
It is revealed that Marshall is Rex Bailey's stunt double protégé on the set of Project Ronkonkoma, which now becomes an integral part of this story. It's easy to see why this trio had their say: Marshall P. Pope was the sniper who shot Sazz.
***Disclaimer: This article contains spoilers to episode 9 of Only Murder in The Building Season 4***
Who is Rex Bailey in Only Murders in the Building Season 4?
Rex Bailey is a lumpy, blonde-haired man who Sazz mentored during his stunt double days. Sazz failed to take proper safety precautions which led to a serious accident on the set of Ron Howard's film. He lost his eyebrows as a result of the accident, while Rex probably lost his budding screenwriting career.
In Only Murders in the Building Season 4 Episode 9, Marshall P. Pope unexpectedly returns to the show, where he is now an aspiring screenwriter. Marshall might also be responsible for the murder of Glen Stubbins because Glen had recognized him earlier in the season and questioned his beard; he was already aware about the truth about Marshall’s identity.
How does Season 4 of Only Murders in the Building hint at Rex Bailey being the murderer?
At first, Charles, Oliver and Mabel thought Glen Stubbins was Sazz Pataki's protégé. This changed when they met a bartender outside the hospital. "Actually," the bartender told them, "he's one of only three people who know who Sazz's real protege is. The others were Sazz himself and film director Ron Howard.
The three then decided to meet with Ron Howard to find out the truth. Howard eventually met Charles and Oliver at Charles' favorite Chinese restaurant. Howard revealed to them that Rex/Marshall was Sazz's protégé after showing them a picture of his.
Around the same time, Mabel was in her apartment alone with Marshall helping him with his script for the movie when she found an Only Murders in the Building script on a beer crate. The script belonged to Rex and had Sazz's name on it. Soon after as she was beginning to connect the dots. A text appeared on her phone. It was Charles who was texting her about what he had learned from Howard.
Only Murders in the Building is currently available to stream on Disney+ and Hotstar.