Someone has probably already done it but I decoded the message from TFP and it says
AM HERE ABE SLANEY
which is an obvious reference to “The Adventure of the Dancing Men”
I researched it
(on wikipedia like a professional) and found this:
The little dancing figures are a main part of the mystery, which seem to be driving Mr. Hilton Cubitt’s young wife Elsie Patrick to distraction. He married her about 1 year ago, and until recently, everything was well. She is American, and before the wedding, she asked her husband-to-be to promise her never to ask about her past, as she had had some “very disagreeable associations” in her life, although she said that there was nothing that she was personally ashamed of. Mr. Cubitt swore the promise and, being an honourable English gentleman, insists on living by it.
The story follows with Elsie getting disturbing coded letters but she never told her husband what was going on. These messages were written by Slaney, who was Elsie’s former fiancé from Chicago. She had originally fled his clutches because he was a dangerous criminal. Slaney came to England to woo her back. Elsie’s husband was killed by Slaney and Elsie shot herself but recovered from her injuries.
I’m not sure what they want to tell us but it has something to do with Mary and her death, maybe foreshadowing what actually happend in The Six Thatchers
You should do what mister metokur did and reveal the url of these people because if you didn't they'd probably not believe it as much. Just a tip :o