All chapters

The Old Man in the Corner · Chapter

VI: All He Knew explained

The Old Man in the Corner reveals the intricate scheme behind the Phillimore Terrace diamond theft, explaining how Mr.

What happens

The Old Man in the Corner reveals the intricate scheme behind the Phillimore Terrace diamond theft, explaining how Mr. Knopf and his servant Robertson—likely twin brothers—orchestrated a double impersonation to steal Mr. Shipman's diamonds. He details the use of a drugged wine, a forged letter, a staged fight with a tramp, and the careful avoidance of being seen together to maintain the illusion.

Themes in this chapter

  • Deception and Forgery

    The entire theft relies on forged diamonds, a forged letter, and the impersonation of one man by another.

  • The Power of Observation

    The Old Man demonstrates how careful observation of details (e.g., no one seeing Knopf and Robertson together) reveals the truth.

  • Appearance vs. Reality

    The respectable diamond merchant and his servant are actually criminals; the tramp is a disguise; the theft appears to be a burglary but is an inside job.

Characters to notice

  • The Old Man in the Corner

    Explains the entire scheme behind the diamond theft, revealing the dual impersonation and the roles of Knopf and Robertson.

  • Polly Burton

    Listens to the Old Man's explanation and interjects with questions about Mr. Knopf.

  • Mr. Knopf

    One of the diamond merchants; revealed to have impersonated his servant Robertson and orchestrated the theft.

  • Robertson

    Knopf's servant; actually the accomplice and likely twin brother, who impersonated Knopf and helped execute the theft.

  • Mr. Shipman

    The jeweler who was drugged and robbed of his diamonds; the victim of the scheme.

  • Mr. Francis Howard

    The detective who investigated the case but was misled by the impersonation and never caught the thieves.

Key passages

  • The whole trick lay in one simple art, which those two cunning rascals knew to absolute perfection, the art of impersonating one another.

    The entire deception was based on the two criminals' skill at pretending to be each other.

    The Old Man summarizes the core method of the theft.

  • They are brothers, presumably⁠—twin brothers, I should say.

    The Old Man deduces that Knopf and Robertson are likely twin brothers.

    Reveals the relationship behind the impersonation.

  • It had all been foreseen, and Robertson must have been constantly on the watch.

    The criminals planned every step, with Robertson keeping a continuous lookout.

    Highlights the premeditation and vigilance of the thieves.