The Voice of Merrill

A struggling author who becomes romantically involved with the murdered blackmailer. He is one of the three suspects the inspector shadows, and he ultimately faces the possibility of confessing to protect Alycia. The tension centers on his integrity and career in the face of mounting pressure.

Roach's wife, bored with her loveless marriage, who begins an affair with Allen. She pressures Allen to pass off the radio play as his own work to boost his career. She poisons Roach, hoping the death will be blamed on his illness, and reacts with fear when autopsy looms, trying to derail confession.

A playwright with a heart condition who writes the radio play The Voice of Merrill. He suspects Allen is Merrill and grows angry that Allen won’t publicly claim the credit. Though Roach dies, his posthumous revenge aims the final twist toward the killer, shaping the investigation’s direction.

A publisher who was blackmailed by the dead woman, losing thousands of pounds. His motive stems from fear of exposure, keeping him cautious and evasive as the case unfolds. He embodies a financial and reputational threat within the crime network.

The lead detective who shadows the suspects and pursues the truth through alibis and motives. He pieces together a web of relationships and uses the final broadcast as a critical clue. His insight turns the narrative toward the revelation of the killer.

The physician who treats Roach and conducts the autopsy that initially points to natural causes. He provides medical perspective on the death, contributing to the investigation's factual backbone. His role intersects with questions of responsibility and evidence.

A police sergeant assisting Inspector Thornton, helping to verify alibis and interview suspects. He adds procedural momentum to the pursuit of the truth and supports the investigation's methodical pace.

A supporting character listed in the cast; the provided summary does not detail her actions. Her specific role and influence on the plot are not described in the given material.

A minor character whose actions are not described in the provided summary. The exact role and impact on the plot are not detailed here.