The Case of the Registered Letter

The Case of the Registered Letter is a crime fiction novel written in the early 20th century by Auguste Groner. It follows Joseph Muller, a secret service detective in the Imperial Austrian police, as he investigates the murder of John Siders, who is found dead under suspicious circumstances. The plot centers on Albert Graumann, wrongfully accused of the murder, and his aunt's efforts to prove his innocence. As Muller uncovers layers of deception, he reveals that Siders may have staged his own death, raising questions about morality and justice.