Who murdered Oliver Whyte? Roger Moreland. Wearing Whyte's coat, he enters the cab after the driver mistakes him for Brian, uses the chloroform from the coat to subdue Whyte, and steals the marriage certificate.
Why does Brian refuse his alibi? The dying Rosanna Moore entrusted him with the secret of her lawful marriage to Mark Frettlby. Revealing where he spent the night would expose Madge's family scandal.
What is Mark Frettlby's crime? He abandons Rosanna, permits Whyte to use the secret against the family, pays Moreland after learning of the murder, and suppresses the truth. He is morally compromised but is not Whyte's killer.
Who is Sal Rawlins? She is the daughter of Mark Frettlby and Rosanna Moore, and therefore Madge's half-sister. The surviving men conceal this fact while settling an income on her.
What happens to Moreland? After admitting the murder and being arrested, he hangs himself in his cell without leaving a confession.
Why is Frettlby's confession burned? Brian, Calton, Chinston, and Kilsip decide that publication would only disgrace Madge and expose Sal after the killer's death. The legal mystery is solved privately but never fully disclosed to the public.
Themes and What the Ending Means
Public evidence and private truth The newspaper, inquest, and trial create official versions that are plausible but incomplete. The decisive truths remain in letters, memories, and private confessions.
Respectability as concealment Frettlby's wealth protects a history no less damaging than the crimes associated with the slums. Social position determines which secrets receive sympathy.
Loyalty versus justice Brian keeps silent to protect Rosanna and Madge even at the risk of the gallows, while the final group protects Frettlby's reputation after solving the case. The novel repeatedly treats silence as both noble and corrupt.
The city as evidence Routes, clocks, railway times, cab stands, and neighborhoods are essential to the deductions. Melbourne's geography makes and unmakes the case against Brian.
Inheritance and legitimacy The murder document threatens not only reputation but the legal and emotional identity of two daughters who did not create their father's wrongdoing.