Horowitz is dismayed that the story now involves a locked-room mystery. Although he knows that it is possible that Hawthorne is wrong, and that Roderick’s death isn’t murder, he trusts Hawthorne’s instincts. As much as he doesn’t like the idea of trying to make a locked-room mystery seem plausible, he also realizes that without it, he will have no plot twist and a very short book. He is waiting for Hawthorne to come over and look at Part 5. In the meantime, he tries to think about who the killer might be.

He suspects May and Phyllis. Although they are probably too elderly to have shot the crossbow, Ellery’s death is a powerful motive. He also doesn’t believe their story about the convent and the inheritance—the story about a dead aunt is too obviously cliché. Sarah is the next suspect on his list, and he wonders what the connection is between her and Roderick. He also realizes that Sarah might be connected to Roderick’s missing phone.

Tom and Gemma Beresford are also good suspects; he is misusing alcohol and drugs and fought with Giles. The patient who died, Raymond Shaw, may have been the last straw.