NITS: Openshaw's uncle Elias is found dead drowned with his face submerged in a two-foot garden pool. The coroner brings in a verdict of suicide. How many people attempt to commit suicide by holding their face under a garden pool? And for that matter, how did the Klan agents manage to kill Elias in this manner without leaving any signs of violence? Once again we have a secret society of murderers displaying supernatural powers (see nits for "A Study in Scarlet.")
If the Klan agents want the papers so bad, how come they make no attempt to recover them after murdering Elias?
Is it likely that the real life Ku Klux Klan of 1887, a strictly domestic and provincial organization, would pursue a former member into another continent just to recover some papers he had?
CHRONOLOGICAL CONUNDRUM: In this case, Holmes makes reference to having in the past being bested by a woman. It would seem that it is Irene Adler he is talking about. But "Five Orange Pips" takes place in September 1887 and "Scandal in Bohemia" won't happen until March 1888.