The Kennel Murder Case (1933)
A precursor to the Thin Man series, starring William Powell as a detective (but without the very supplementary Myrna Loy). And this is directed by none other than Michael Curtiz ("Casablanca" and "Mildred Pierce"), and you can often tell, scenes characteristically complex with lots of people and foreground/background. As a whole the movie races along, to the point that the huge cast (all introduced with visual vignettes at the start) is confusing. But hang in there. because a third of the way through Powell kicks in full time.
There are few actors like William Powell in the history of American film. He is peculiar in charming ways, and makes no bones about it. He lacks any sense of what we might think of as cool or hardness--there's no Bogart in him, no Cary Grant of course, nothing but what a character actor might have. And he made it a virtue, visible even here. The rest of the cast is good or very good, with a few other recognizable faces, and it gels increasingly as you go until a series of dramatic whodunnit style conclusions wraps it all up.
Powell's detective, Philo Vance, was a snobby socialite, and the plots have a quality of private detective vs. police (which gets used in a lot of these kinds of series, of course). There are four movies with Powell playing the part (and many others with other actors in the role. This is the fourth, and best of them, the first going back to the dawn of sound, 1929. It's not as slick or warm (or sophisticated) as "The Thin Man" series, which is a high water mark of the effete detective, but it's terrific in its own way, and really well constructed. I'd not miss it.