Actually, it is rather an odd Sherlock Holmes story to choose, if the kids are only going to read one. I’d say “The Hound of the Baskervilles” would be a better choice. Or a collection of the earlier stories, when Watson first meets Holmes.
It does certainly present the Mormons in a bad light. But it does have some historical basis. Whether it’s factual or not I’ll leave to others to argue.
Watson and Stamford intrude upon Holmes at a laboratory in which Holmes has just discovered a reagent (you will recall that Holmes, in the Conan Doyle oeuvre was a brilliant chemist) that was precipitated solely by hemoglobin, thus a definitive test for blood traces, which was otherwise unavailable at that time.
This attempted banning of the first Conan Doyle Holmes novella is neither more nor less than the PC addicts run amok. Please keep in mind that Conan Doyle wrote the interlude of the story, "On the Great Alkali Plain", et seq., to allow the killer, Jefferson Hope, to explain his motivation for the murders, not to bash the Mormon religion. Any faith has had, always, those adherents who mouth the creed and violate it an hour later, and such were Drebber and Stangerson, both renegade Mormons.
Why this alleged "educational" establishment should attempt to ban a quite plausible story, in its day, of love and revenge, is utterly beyond me. As far as that goes, Hugo Baskerville's conduct was infinitely worse, and storywise offered much less in the way of the exhibition of the science of detection. (Read it again, m'FRiend, I've nothing to sell you, and you will see straightaway for yourself).
Best to you, as always, and FReegards!
"The Hound of the Baskervilles" is a long story, with many actors, several sub-plots, and with many motives. It may be also a pretty scary story for a younger student, with a large dog running around and attacking people. It involves a good deal of adult matter as well; one key observation, for example, is the unusual behavior of the protagonist with regard to his "sister." This may be lost on a 6-grader. But the demise of the spaniel will surely be noticed.
I agree, Hound of the Baskervilles would be my first choice. “And above all, avoid the moor, when the powers of evil are exalted.” !!!