Conover is arrested, but without evidence, the police can only hold him for 48 hours. Over those two days while Conover is imprisoned, six busts of Napoleon, including the one containing the pearl, are sold. One by one, Conover tracks down the owners of the busts, and then uses a back-breaking brute, the Oxton Creeper, to kill them.
Investigating the first murder, Holmes suspects a connection to the theft of the pearl. Since the body is found in a litter of broken china, Holmes deduces that the killer was searching for something. Holmes knows he's on the right track after Conover, disguised as a former client, visits Baker Street and leaves a large book for Holmes. The book actually contains a springing knife, intended to kill Holmes when he opens the book. Thanks to Holmes' familiarity with tobacco ash, he realizes that the visitor was not who he pretended to be, and is suspicious of the book.
Two more murders occur and the bodies are also found in a litter of broken china. Holmes and Watson are able to find pieces of a Napoleon bust in the broken china from each murder scene. They question the museum guard who admits that Conover ran into a pottery shop just before he was captured. Gelder, the pottery shop owner, sends them to Amos Hodder, a London shopkeeper who bought six busts of Napoleon. Holmes recognizes the young woman working in the shop as Naomi Drake, and he learns that she broke two busts of Napoleon on her first day there. The other four busts were in turn sold to four different people: the three murder victims and Dr. Julian Boncourt.
Realizing that Dr. Boncourt will be the next victim, Holmes disguises himself as the doctor and waits for Conover in the doctor's surgery. While Conover holds a gun on Holmes, Holmes tricks the Creeper into turning on his master, and then Holmes shoots the Creeper.
After Watson arrives with the police, Holmes breaks open Dr. Boncourt's bust of Napoleon and finds the Borgia pearl. Holmes comments thoughtfully, "The Borgia pearl...with the blood of five more victims on it." To which Watson says, "Anyway, Conover was one of them." Holmes continues, "What's Conover? No more than a symbol of the greed and cruelty and the lust for power that has set men at each other's throats down through the centuries. The struggle will go on, Watson, for a pearl, a kingdom, perhaps even world dominion...until the greed and cruelty has been burned out of every one of us, and when that time comes perhaps even the pearl will be washed clean again."
Even though the similarity to Conan Doyle's story is only slight, The Pearl of Death is nevertheless a very entertaining film with its share of action and suspense. The atmosphere, especially in the final scene with the Creeper, is gripping. The sets are wonderful in their detail. Look for the Persian slipper and other well-known Holmesian artifacts in the 221B Baker St. set. The extras and details in the museum set and Gelder's pottery shop also give them an appearance of authenticity.
Several clever disguises are used in this film: Naomi as a matchgirl, a shopgirl, and a kitchen helper; Conover as a bibliophile and a museum workman; and Holmes as an elderly clergyman and Dr. Boncourt. In addition, Holmes impersonates Conover's voice on the telephone. Rathbone actually does imitate Miles Mander's voice--it's not dubbed.
The film also contains humorous dialogue such as the following, after Lestrade reports the murder of Horace Harker* to Holmes and Watson:
*There is also a Horace Harker in "The Adventure of the Six Napoleons," but he is a newspaper reporter, and he wasn't murdered.
The TV Guide Motion Picture Database review of this film erroneously states that the thief hid the pearl in one of six busts of Beethoven. (There were busts of Beethoven in Gelder's shop when Holmes and Watson questioned Gelder.)
Although the Creeper was killed at the end of The Pearl of Death, the public liked the character so well that Rondo Hatton was cast in the role of the Creeper in Jungle Captive, House of Horrors, and The Spider Woman Strikes Back.
.Watch the trailer for The Pearl of Death: