I've never read the Valley of Fear myself, only the synopsis. However, since I never missed even one chapter of Detective Conan, I notice that the story of Shuichi Akai infiltrating the org is strikingly similar to that of the Pinker Agent Birdie Edwards, who passed himself off as the infamous conman John McMurdo, who boasted of counterfeiting and betraying his own partner to gain trust from the Ancient Order of the Freemen's Bodymaster McGinty.
Birdie, much like Shuu, also fell in love with the daughter of another member of the Order, Ettie Shafter. Ettie reciprocates his feelings. This however earned "McMurdo" the rivalry of Ted Baldwin, Ettie's suitor. However, the Order soon caught wind of a certain "Birdie Edwards'" infiltration, evenm tho they don't know that "McMurdo" is in fact Birdie Edwards. Birdie tricked the order into laying a trap for "Edwards," only to reveal himself to be the very Pinkerton Agent they're ambushing and had his colleagues arrest them all.
After this incident, however, Birdie had to flee from the vengeful Ted Baldwin. He arrived at England and changed his name to John Douglas, where he married his 2nd wife (Ettie already dying a natural death, thanksfully). Even tho' Ted successfully tracked him down, Birdie/Douglas killed Ted in a brawl when Ted's sawn-off shotgun accidentally went off and effectively destroyed Ted's face. Douglas attempted to pass Ted as himself. Nevertheless, Douglas' scheme this time is seen through by Holmes. Douglas was acquitted with a fair trial pleading self-defense.
However, Douglas is ultimately killed (a deed which Holmes attributed to Professor Moriarty) while attempting to flee England again, because Ted Baldwin also enlisted Moriarty's help in the former's effort to have his vengeance on Douglas.
Now to the main part.
I am NOT suggesting that Aoyama completely plagiarized Conan Doyle. You know, stories about moles from law-enforcement force infiltrating criminal organization abound. I just point out similarities. And I deduce that this is the way Aoyama paid his homage and tribute to Conan Doyle.
Nevertheless, that there are so many similarities between Aoyama's and Doyle's respective works that worries me. Listed below are the equivalents between each work, Doyle's characters at the left side and Aoyama's right:
John McMurdo / John Douglas / Birdie Edwards - Shuichi Akai
Ettie Shafter - Akemi Miyano (why did Akemi not die naturally ? )
Ted Baldwin - Gin (I hope Gin's face got blown off the same way Ted met his fate )
Birdie's 2nd wife, Mrs. Douglas - Jodie Starling
Cecil Barker - James Black
and last but not least
Moriarty - That Person, Anokata, The Black Org's Boss.
At the end of the story, Holmes assured Birdie's friend, Cecil Barker, that Moriarty would pay his price (ultimately at Reichenbachs Fall, my many thanks Sir Doyle !). However, I am sad that Doyle killed off Douglas. So despite many fans theory about Okiya Subaru being Akai, I am afraid that Akai in fact died, even tho' this can be interpreted as a sacrifice to bring down the org once and for all.