Other clues begin to surface, including Kinkaid's unusual collection of books on chemistry and poisons, and a loaded gun found in Virginia's bedroom.

Llewellyn's recently altered will, in which she disinherited Kinkaid, making it apparent that Lynn and Amelia would be the only ones who would benefit from Mrs. Llewellyn's daughter, who admits that she too had a spat with Virginia. Llewellyn, who recalls having quarrelled with Virginia before she was poisoned, and Amelia, Mrs. Markham begins his investigation of the murder by questioning Mrs. At the same time, Doris informs Vance that Virginia has died at the Llewellyn house. Vance assigns Sergeant Heath to help stake out the casino that night, but their presence does not prevent Lynn from suddenly collapsing at the card table. Doris immediately recognizes the return address as being that of the Llewellyn's townhouse in Closter, and notices that the letter was typed on her typewriter. Vance takes Doris to his home, where he and District Attorney Markham show her the mysterious letter. Llewellyn's secretary) are introduced to each other and Doris immediately takes a liking to Vance. Llewellyn's son Lynn and his wife Virginia, Virginia announces that she has decided to leave the house and go to Chicago. At the end of the bitter quarrel, which involves Mrs. Priscilla Kinkaid-Llewellyn, the matriarch of the household, and stumbles into one of the family's many quarrels. Vance visits the Llewellyn estate, which is run by Mrs. Gentleman detective Philo Vance begins an investigation when he receives an anonymous letter stating that society man Lynn Llewellyn will be in danger when he appears at the casino owned by his uncle, Kinkaid.

It was the ninth film in the Philo Vance film series. Marin from a screenplay by Florence Ryerson and Edgar Allan Woolf, based on the 1934 novel of the same name by S. Rosalind Russell is in the supporting cast. The Casino Murder Case is a 1935 American mystery film starring Paul Lukas and Alison Skipworth.

The casino movie cast