The mysterious affair at Styles

I've read roughly the first 17 pages of The Mysterious Affair at Styles. A friend who's a fan of Agatha Christie says her mysteries are the kind you can solve. What do I think so far?

(Needless to say, this post will have spoilers for the early part of this book.)

Lawrence has done a few suspicious things:

1. The day before the murder, everyone went to Cynthia's dispensary at the local hospital. When everyone went out on the balcony to look at the outside wards, Lawrence hung back inside the station a few moments. (Page 9 in my copy.) The station is home to all kinds of medicines and some things that could act as poison. Also — right before that, Cynthia said (joked?), "Come on, let's have tea. We've got all sorts of secret stores in that cupboard. No, Lawrence—that's the poison cupboard. The big cupboard—that's right."
2. The night of the murder, it's Lawrence who wakes up Hastings, our narrator. It's Lawrence who informs him that "We are afraid my mother is very ill. She seems to be having some kind of fit. Unfortunately she has locked herself in." (That's Mrs. Inglethorp, the stepmother.)
3. The night of the murder, Hastings and Lawrence broke into the room from Alfred-the-fake-husband's side, trying to render aid to the victim (Lawrence's stepmother). After breaking in, Lawrence looks in the direction of the fireplace and is horrified, shocked, or otherwise extremely unsettled. Hastings notes only a row of ornaments on the mantelpiece and some ashes in the fireplace. So: Something is missing from the mantelpiece, or maybe there is something about the ashes.
4. After the doctors pronounced their diagnosis of "Maybe it's poison," Lawrence got angry and said it was bullshit, definitely not a poisoning. (Page 16.) That seems like the kind of thing you would say if you had something to hide in the invetigation.

On the other hand, there are some other facts:

1. The day before the murder, Mrs. Inglethorp looked upset and insisted she needed to write some letters. She spent that whole afternoon and night writing letters. She might have been especially agitated about or with Cynthia, but she denied it when Cynthia asked.
2. The day before the murder, Mrs. Inglethorp had a great big argument with her husband Alfred over who knows what.
3. The day before the murder, Mrs. Inglethorp went to bed with her coffee, as yet untasted.
4. Mrs. Inglethorp recently sent away her companion, servant, and "factotum," Evie Howard, after Evie got in a fight with Alfred.
5. On the night of the murder, Alfred, the mysterious stranger who was the dead Mrs. Inglethorp's husband, is gone, and the bed in his room has not been slept in.
6. Alfred left earlier that day to see Dr. Bauerstein off, and said he was going to visit their agent to talk about 'those estate accounts.' He took the latch key with him so nobody would need to let him in the house. That means nobody in the house could have used the latch key. On the other hand Dr. Bauerstein could well have stolen it if he wanted.
7. According to John, Alfred claims to be "a second cousin of Evie's, though she didn't seem particularly keen to acknowledge the relationship."
8. There's a "Mrs. Raikes," wife of Farmer Raikes, and Evie says Alfred spends an awful lot of time over there with Mrs. Raikes. Evie all but says he's having an affair with Mrs. Raikes.
9. Mrs. Inglethorp's sons (and daughter-in-law?) suspect Alfred. He's a fishy character.
10. Evie, Mrs. Inglethorp's servant, had just been dismissed for questioning Alfred's integrity/loyalty.
11. All the doors to Mrs. Inglethorp's room are bolted.
12. John Cavendish, Lawrence's brother, had been complaining to Hastings the other day about not getting enough money from their stepmother, Mrs. Inglethorp. Lawrence was also in dire straits — "He's gone through every penny he ever had," as John said.
13. John Cavendish was already awake by the time that Lawrence woke up Hastings. Hastings and Lawrence met him outside Mrs. Inglethorp's room.
14. John's and Mary's rooms (plural) are situated so that they could get to Mrs. Inglethorps and they'd only have to pass Alfred's room on the way. Nobody else has such a secluded route except Cynthia. Lawrence would have to walk past John's and Mary's rooms to reach Mrs. Inglethorp's.
15. Mary Cavendish is a good friend of Dr. Bauerstein, a London doctor and poison expert — "one of the greatest living experts" per John. They've been going on long walks and chats together lately.
16. Mary Cavendish mentioned chatting with Dr. Bauerstein about poison, and how "owing to the general ignorance of the more uncommon poisons among the medical profession, there were probably countless cases of poisoning quite unsuspected."
17. Mary gets up at five every morning "to milk" and doesn't turn up until lunchtime.
18. The day before the murder, Mary Cavendish looked agitated. She denied having walked with Dr. Bauerstein that day. She went directly to speak with Mrs. Inglethorp. She was demanding that Mrs. Inglethorp show her something, Mrs. Inglethorp refused saying it's "nothing to do with that matter" and adding "I tell you it is not what you imagine. It does not concern you in the least."
19. The day before the murder, Mary Cavendish brought Cynthia, Hastings, and John the coffee that Mrs. Inglethorp drank. She seemed excited when she did. She said she'd pour it out for Mrs. Inglethorp and asked Cynthia to take it up. However, Cynthia didn't — it was Mr. Alfred Inglethorp who poured the coffee and brought it upstairs.
20. The day before the murder, Dr. Bauerstein turned up at the house, covered in mud, in the company of Alfred Inglethorp. He says he was looking at a rare species of fern when he slipped and fell in a pond.
21. Cynthia is an orphan living in Mrs. Inglethorp's house at Mrs. Inglethorp's pleasure. Mrs. Inglethorp often calls on her to do various chores — in Hasting's view, [Cynthia's] position was a dependent one, and... Mrs. Inglethorp, kind as she might be in the main, did not allow her to forget it.
22. Lawrence and Cynthia have some kind of weird thing together. He has a crush on her. She has been "shy" with him, but then the day of the murder they were chatting pleasantly. So maybe there is something mutual there.
23. On the other hand, not so long ago Cynthia was walking arm in arm with John. Maybe she and John are having an affair. Lawrence was watching and got pissed off about it because of his feelings for Cynthia.
24. Cynthia's room is adjacent to Mrs. Inglethorp's, but Lawrence's is on the opposite end of the house from Mrs. Inglethorp's.

We can cross off a few characters easily. Hastings, the narrator, and Hercule Poirot, his buddy and probably the protagonist, are not the murderer. Dr. Wilkins, Mrs. Inglethorp's physician who (under Bauerstein's advisement) diagnosed her with poisoning, wouldn't be, he wasn't around enough nor relevantly interested. Obviously it can't be Alfred or we'd have no story. :) It can't be Evie, because she's not even here. Clearly Alfred is up to something sketchy, but not murder.

That leaves five suspects: John, his wife Mary, Lawrence, Cynthia, or Dr. Bauerstein.

John looks somewhat suspicious. He has his grievance — money. His wife's in with the poison man. John was up before Hastings the night of the murder. But this is all pretty circumstantial, so I'm gonna say: Probably not.

Mary on the other hand looks incredibly suspect. Mary has been chatting with Dr. Bauerstein, the poison man, who could have hooked her up with some poison. She's casually brought up poison as a way to get away with murder. She got into a big fight with Mrs. Inglethorp the day before the murder. She brought the coffee. Mrs. Inglethorp did not drink her coffee until she was out of sight, so it could have had poison. It looks pretty good for Mary having done the murder. A question I have left is, how'd the doors get bolted and Mary looks clean? Also: Looking back, it seems that (a) Mary brought the coffee for three people who did not die of drinking it, and (b) Mary did not actually pour the coffee, Alfred did. She doesn't actualy have the opportunity. So I'll say: Maybe.

As discussed, Lawrence looks super sketchy, but I don't know if he's the murderer. He looked shocked at the missing item or present ashes. I would guess that this item is implicated in the murder — either a means or a motive. Maybe a will that was burned? That seems like a thing that, if it were burned, he'd be horrified. That could mean Lawrence gets nothing, which is a bad deal for him. Or: Maybe there was poison on her mantelpiece? I strongly suspect Lawrence stole something from the nurse's station, maybe that was it. It couldn't have been an obvious one, because that would have raised questions. It must have been in a nondescript or a medicine bottle if that's what's there. Why store it there on the mantlepiece, though, where it is so obvious? In any case, Lawrence's shock suggests that he wasn't the last person in the room. So if he was the murderer, someone else would have to have gotten in here after he poisoned his stepmother. That seems unlikely, but not impossible — maybe this is just a complicated story.

It's plausible Cynthia did the job. If she and Lawrence have a thing, then she had two levels of motivation: Make my boyfriend rich, and get rid of the old hag that's always hassling me. She's got the means — the poison cabinet at the dispensary. But did she have the opportunity? They say the door between them is always locked. She would have had to get up and go around to the front door, where she is much more at risk, or go all the way around through Alfred's room, which is an even bigger risk. But: She did bring if not pour Mrs. Inglethorp's coffee the day before the murder. So: Maybe.

Dr. Bauerstein is the poison guy, so he'd know how to poison her. He might have stolen the latch key from Alfred. He's got the means, in theory. But there's no motivation — why bother? And it would be awfully strange of him to insist on diagnosing her with poison. That would seem to draw attention to himself. Unless he thought he could get away with it and wanted to hurt someone else with the investigation... but there's no evidence of that so far I think. As far as opportunity goes — he would have had to either climb in her window quietly to do the deed without her noticing, or gotten in through the latch key, come in through Alfred's door or the front door without being spotted, poison her, and then sneak back out. That seems pretty elaborate and unlikely. I'm gonna guess Dr. Bauerstein didn't personally poison Mrs. Inglethorp. It just seems too unlikely. But he might have helped someone else — if anyone, probably Mary.

So here's my best guess so far: Maybe Alfred did do it? John doesn't seem to have the means. Mary had the best chance because she brought the coffee, but she didn't get to pour the coffee, so she couldn't have selectively poisoned Mrs. Inglethorp unless she poisoned the whole batch with some very unusual poison that would only work on Mrs. Inglethorp — nobody else died of the coffee. Lawrence is too surprised at the room's state for me to think he did it. Cynthia doesn't seem to have had the opportunity. Dr. Bauerstein on his own doesn't seem to have the motive. Nobody I thought might have killed Mrs. Inglethorp seems to have gotten the chance, so who knows?