Some really good thoughts there, Kira.
In my opinion, I believe it is entirely possible Elfrieda was experimenting with Luella, but Hitchcock had captured her heart.
I tend to agree with you there. From the contents of the letter, seems to me Elfrieda was flexing her 'psychological influence' muscles, as well as experimenting sexually. And Luella was hooked - and, as you say, likely a very needy person.
OTOH, this is exactly the type of person who can get sucked in by a mesmerizing, cultish person like Hitchcock.
Yes, exactly - and Elfrieda spotted her as a good prospect for Hitch's 'classes', too, urging her to attend. I really want to know if she ever took any..
Just some thoughts on the letter:
Luella wanted answers, said another note found, and she did in fact stalk Elfrieda to Highland Park (meeting her at the station, probably?) some time prior, in order to get those answers. Which means she knew that's where Elfrieda changed trains after work.
From the letter, I'm assuming Luella had intended to send back the books she bought from Elfrieda (but kept them as a souvenir in the end, and perhaps to demonstrate that she wasn't being petty). This, and the apologetic tone in places, suggests to me that there had been some confrontation between them before the letter was written (Oct 20? IIRC). Maybe that was the Highland Park 'getting answers' confrontation.
Luella states that Elfrieda suddenly went cold on her, 'businesslike'. It seems that Elfrieda, having gotten what she wanted from it all (a sale, some experience) and, as you say, maybe realising Luella was a liability, abruptly severed the relationship.
I have to wonder if Luella was part of the "hell" Elfrieda said Hitch got her out of three months before? He admitted she often came to him with personal problems (maybe excuses to drop by and spend time with him?). I also have to wonder, from the fact Elfrieda hadn't seen Hitch in a while, if Elfrieda was 'acting out' her own relationship with Hitchcock, in using and ditching Luella.
It's easy to zero in on a jilted lover (a secret and forbidden one at that) as an obvious suspect, can't blame Ione a bit for that. I mean, what better revenge could a bitter, unhinged ex-lover have than to destroy Elfrieda, leaving her naked and humiliated in the one place sure to make her 'true love' look like suspect No. 1?
But as you say, there's much room for doubt as well. I can't see Elfrieda lying to cover up Luella - and I firmly believe she DID lie, rather than just being delirious. Her own brother is reported to have caught her out a few times, where she slipped up and hinted at others being present. Elfrieda refused to talk about it further, then insisted she'd been talking nonsense. Her brother didn't believe her.
Elfrieda -would- lie to protect Hitchcock, though, I believe. And what better way to get rid of a woman who had become a liability herself, than to have her murdered while sitting at home with a broken leg?
But you know who I would want to humiliate? My husband's lover.
Yes. That's another angle I'd really like to explore. Mrs. Hitchcock would have access to the keys. Her husband was housebound, so the timing was good. She certainly could have had a classic motive.
Would she also lie to protect Hitch's wife?
I'm not so sure Elfrieda's comment ("I can't submit to his love until acceptable to his wife") was just delirious babble. I think it's also possible that in her pained and doped-up state Elfrieda let things slip that she didn't mean to.
"Submit" is an interesting word there. It implies he was the one chasing her -- and Elfrieda was the one holding off, hoping his wife would come 'round to the idea. Perhaps Elfrieda wasn't wholly amoral and didn't like the idea of plain old adultery. She was so very insistent that their love was 'astral' and not physical (which she held to consistently) -- it makes me question whether that was her way of coping with the weird dynamic of their relationship. She really loved him with all her heart, but had to keep it "astral" in order to feel good about herself, while Hitchcock worked on his wife's accepting a menage a trois situation.
I wish to heck I knew what relationship all of the people surrounding Elfrieda really had with one another -- Luella, Hitchcock, Estelle, Barney, Mrs. Rosenhagen..
And (to throw another loop into the mess) -- if the State's Attorney himself was a 'student' (and devoted enough to get Hitch off a robbery charge the next year, sending Hitch Jr down for a stretch on his own) -- who else among the local community was under Hitchcock's spell? Some of the nurses at the hospital? A doctor, maybe? I think all their various statements ought to be examined carefully.
As an aside, and probably not connected but coincidental enough for a mention -- there was another "Raymond Hitchcock' of the era who was a well known Vaudeville act (like Charles Hitchcock) and who (like Charles) later transitioned to film.
This Raymond Hitchcock was a real ratbag who was arrested more than once in connection to some assaults "on young girls" (for which he had been being blackmailed and actually had the blackmailers charged for it), and who went missing around 1910 to avoid the cops regarding those charges. It was a terrible scandal, of course. Some years later, and despite being a highly successful man, he famously declared bankruptcy.