Appearance vs. Reality

Characters and events are often not what they seem, from Mrs. Drabdump's grim demeanor to the seemingly saintly Arthur Constant's hidden complexities, and the final revelation that the detective himself is the murderer.

The initial evidence and circumstances surrounding Constant's death may not be as they seem, setting up a central theme of deception.

Mrs. Drabdump's sense of security from Grodman's presence contrasts with the actual danger; Constant's saintly appearance may mask a darker reality.

Mrs. Drabdump's description of Constant as 'weak-headed' contrasts with his actual cheerful demeanor; Mortlake's arrest and release show the gap between suspicion and guilt.

Constant's public optimism contrasts with his private letter of despondency, and the sealed room appears impenetrable yet a murder may have occurred.