THE TRANS ATLANTIC MYSTERY (1932) -- colorized short mystery

A couple of murderous crooks try to smuggle the famous Stanhope diamonds into New York but they’re double-crossed and killed before reaching New York.

Joseph Henabery directs the 12th and final installment in series of two-reel pre-code shorts written by S. S. Van Dine and starring Donald Meek as the forensic specialist Dr. Amos Crabtree. This time the setting is a luxury ocean liner called the Hellenic, which is making its way from Europe to America. Two jewel thieves, Miller and Waite, hope to fence the stolen Stanhope Diamonds in New York for $150,000. They have a plan to smuggle the gems past customs by using a journalist called Deeks as an accomplice. However, even before boarding the ship in England, Waite (Ray Collins) shoots and kills Miller and, with the help of the dead man's valet Dodge (Walter Kingsford), he assumes Ben Miller's identity before learning that an angry woman named Daisy (Betty Pierce) is gunning for Miller, too.

The Hellenic's captain (Harry T. Morey) is informed by Lord Stanhope that the jewels may be aboard his ship, but he is unwilling to trouble passengers with a search without some hard evidence. Stanhope says he will have to take care of matters himself. And again, nobody knows Daisy is on board with a gun and an ax to grind. As we see the Hellenic approach New York City, Deeks is preparing to board the ship using a quarantine pass and bringing a gun with him, just in case there's trouble.

At NYPD's Homicide Division, Inspector Carr (John Hamilton) receives a cablegram from Scotland Yard asking him to detain Lord Stanhope upon arrival and question him about the murder of an unidentified man in Ben Miller's home. Miller was suspected of the jewel theft and Stanhope had threatened him. Carr asks Dr. Crabtree to accompany him to the docks to meet the ship. But even before the Hellenic arrives, the man thought to be Miller has been found dead in his cabin, shot in the back of the head. A gun is found on the floor.

The Captain says New York has jurisdiction over the case. He invites Carr and Crabtree to investigate. They question Stanhope and examine his gun, which was too big to have killed the victim. Dodge has an alibi confirmed by the purser of changing currency at the time of the homicide. Then, Daisy's name comes up. She admits the gun they found was hers, but says it had been stolen from her purse. We learn Daisy was the former Mrs. Miller. And when she sees the body, she immediately claims its not her ex at all. Of course, Car and Crabtree solve the mystery within a couple of minutes as always, with the help of a confession this time. But there will be no arrest. The culprit commits suicide rather than be taken into custody.