The Scotland Yard Mystery (1934)

Starring Gerald du Maurier, George Curzon, Grete Natzler, Belle Chrystall, Leslie Perrins
Directed by Thomas Bentley

(actor & director credits courtesy IMDB.com)

A Scotland Yard superintendent finds himself in a battle of wits with a doctor also working for the Yard who has masterminded a scheme to fake men's deaths and collect their insurance money.

With an alternate title of The Living Dead, it's easy to at first assume this might be a horror film, but the men who "die" are actually given a serum to simulate death, and revived by an antitoxin.  Nonetheless, this is an entertaining British mystery more focused on the cat and mouse game between superintendent Du Maurier, and villainous doctor Curzon.  Curzon in particular is given clever dialogue to defend himself, even when Du Maurier witnesses him poison one of his confederates to keep him from talking.  I enjoyed seeing how Scotland Yard conducts their investigations in the film's setting and era, with plainclothesmen tailing suspects, and interrogations limited by the rule of the time banning use of the third degree.  Although I wouldn't say any of the cast especially stood out, this is a competently made and cleverly written film.