After Blackmail, Hitchcock made another suspense film which was again an adaptation of a stage play. But Murder! is in a different genre, the English style detective story, rather than a thriller.
Herbert Marshall was the Master's first really successfully cast leading man, though with his false leg, it's hard to imagine him doing more energetic scenes and he wasn't used again until Foreign Correspondent (1940). He plays an aristocrat on a jury who begins to question the guilty verdict and decides to investigate. Hitch regular Edward Chapman is enjoyable as Marshall's sidekick.
There's a famously innovative scene in the film when we hear Marshall's interior monologue. There was no dubbing at the time, so a recording was made and was played back as Marshall shaved, staring mutely into the mirror, while a live orchestra accompanied!
There's an exciting climax when the murderer, a cross dressing trapeze artist, is closed down by our amateur detectives and he hangs himself on his rope. Another Hitch baddie who falls to his death. While the character's sexuality is handled quite sensitively, there are some dated reflections on him being of mixed race. It's a touch slow, a bit creaky, but it still passes as genuine entertainment.
A murder mystery that gives no red herrings, just points us exactly at the solution and includes some unfortunate racist and other inappropriate attitudes of the time.