Holmes determines from the fact that there was a recent break-in at Russell's house, Russell's anxiety and distraction, the murder of the psychiatrist, and the most recent attempt on Russell's life, that there is something serious amiss. He hires Dashiell Hammett to join his investigation.
Holmes deduces from the fact that there was a recent burglary at Russell's residence, Russell's heightened anxiety and preoccupation, the murder of the psychiatrist, and the most recent assassination attempt on Russell's life, that there is something grave happening. He recruits Dashiell Hammett to collaborate with his investigation.