When the cops are at the suicide/murder scene in the flop house, James Flavin says to Robert Douglas: " Junior, you're making camels out of cloud formations." This is a reference to Shakespeare's Hamlet, Act 3, scene 2.
The "forty bucks a day" charged by the Glorietta Springs Hotel (as told by Fritz, the police lab man) is equivalent to $510 in 2020.
The book Jo Anne Rice (Helen Westcott) is reading at the hotel desk is Ayn Rand's "The Fountainhead," filmed by Warner Bros. in 1948.
Filmed June-July 1948, but not released until 1949, by which time one of the participants, Leo White was already dead. He died in September 1948.
As Lt. Landers (Robert Douglas)and Jo Ann (Helen Westcott) sit in the bar, the background music is, "With a Song in my Heart." Four years later, in a movie of the same title, Helen Westcott would play Jennifer March in the film biography of Jane Froman, who made famous this song.