Only Murders in the Building full title was crafted by co-creator and star Steve Martin

dailymail.co.uk:

Steve Martin returns to the small screen for the first time in years with Hulu's Only Murders in the Building, and he's also responsible for the unique title.Martin, 76, stars alongside longtime collaborator Martin Short and Selena Gomez in the new series, which debuts on Hulu on Tuesday.The comedian also co-created the series with showrunner John Hoffman, who revealed in an interview with The Wrap that the title was all Martin's idea.

Title:Steve Martin returns to the small screen for the first time in years with Hulu's Only Murders in the Building, and he's also responsible for the unique title'That choice was firmly in the mind of Steve Martin from the very beginning,' Hoffman revealed.'He presented it to me and said, "I feel this has to.