The man might have died in a fit; but then the jewels are missing," mused the Inspector, "Ha! I have a theory. These flashes come upon me at times... What do you think of this, Holmes? Sholto was, on his own confession, with his brother last night. The brother died in a fit, on which Sholto walked off the treasure! How's that?" "On which the dead man very considerately got up and locked the door on the inside," said Holmes.

He had maintained a platonic relationship with Jean while his first wife was still alive out of loyalty to her. A sequel to A Study in Scarlet was commissioned and The Sign of the Four appeared in Lippincott's Magazine in February 1890 under agreement with the Ward Lock company. Conan Doyle fathered five children.

He was a prolific writer whose other works include fantasy and science fiction stories plays romances poetry non-fiction and historical novels.