Per Ronald Knox’s Ten Commandments for Detective Novelists, ‘The criminal must be mentioned in the early part of the story, but must not be anyone whose thoughts the reader has been allowed to know.’
Introduced in the first chapter as the first marriageable man of Emma’s acquaintance, Mr. Knightley is the first and most obvious suspect – the man most likely to confess his love for Emma before the novel’s end. Pay attention to his behavior, since it will be the most instructive for Crowley as a romantic hero from Aziraphale’s preferred reading.
However: Mr. Knighley is unbearably sanctimonious. What does he know about the skill it takes to arrange a successful match? How many has he arranged? There is something between the do-nothing and the do-all. Match-making can take a light hand or a heavy one, but above all it takes a balance. A lucky guess is never merely luck. It requires social acumen and insight, which Emma aptly demonstrates. The poor girl goes through such efforts to suppress her own disappointment for the cheer of her father, which will never be appreciated by him, even as she plans everything to his benefit
Here in his notes, Claudius looked up and directed his complaints to Galahad, rather than write every one down. At further length, he spoke on Emma herself – a young woman who experienced an easier childhood than Claudius, but whose sensibilities he found relatable and admirable.
“And consider this," he said, "her mother died when she was young. Her age, and the solace of her governess, were the only reasons she never grieved. So of course she’ll be newly melancholy when her governess leaves her. When my own mother died … well, my mother was a cold-hearted harpy, and Gertrude preferable as a queen to her in every aspect. Gertrude has always been the family I prefer. In Emma’s case, Mr. Knightley is akin to a brother through her sister’s marriage, which is why they’ve such familiar conduct between them – it is going to be Mr. Knightley who confesses, isn’t it? I despise Mr. Knightley. I can’t possibly recommend him as a model to Crowley.”
As to Mr. Woodhouse, who Claudius already dismissed as an ungrateful and onerous father, he had written one more observation:
Mr. Woodhouse mentions Mrs. Weston always turns the lock the right way around and never bangs it. I doubt locked room puzzles are a mainstay of romances, but it should still be noted whenever someone mentions room locks.
Other suspects, alluded to in the beginning: Mr. Elton – who Emma admires and intends to arrange a match for – and Mr. Frank Churchill – who has not yet been introduced, but who is of a marriageable age, and whose circumstances are expounded upon in the second chapter. Per Knox’s Eighth, all clues must be presented. Narration in this amount of detail suggests some clue. Mr. Perry is the apothecary, which will be relevant if poisons appear.
Harriet Smith is, clearly, the Watson, whose intelligence must be slightly below the average reader’s. (Knox’s Ninth.) But she is also quite charming to Emma, who is struck first by her beauty. By the end of the novel, Emma may realize her affections extend to those of her same sex, whose company she currently desires. That makes Harriet another suspect, and perhaps the most promising one. None of Knox's commandments forbid it.
Claudius shared this speculation with Galahad, as he read aloud the words of Harriet's introduction. "Look, here, it says she was a very pretty girl, and her beauty happened to be of a sort which Emma particularly admired and Emma was as much pleased with her manners as her person, and quite determined to continue the acquaintance. Emma never thinks this way about Mr. Knightley." He moved on to the part where Emma admired Harriet's soft blue eyes, before gazing too long on Galahad's. With a flush, he could only return to his notes.
Mr. Martin I will not mark as a suspect, but he may well be an obstacle and rival. His favor for Harriet is obvious, and if they wed, it will remove Harriet from Emma's social circle. Emma's genteel disdain for the match is just as obvious, however she cloaks it as concern – perhaps her first hint of romantic jealousy?
"Harriet and Mr. Elton? What are you thinking, Emma?"
Claudius had the grace to look apologetic for this outburst, which was not planned. To Galahad, he explained, "I well understand wishing to be useful to one's friends and loved ones. But Emma's sabotaging her own happiness, if she thinks marrying Harriet to Mr. Elton will bring anything but the same melancholy she felt on losing Mrs. Weston to marriage, hundredfold. Harriet is Emma's chief romantic prospect, mark my words. And the next chapter ..." He flipped a few pages ahead. With an air of brisk conclusion, he said, "It's all Mr. Knightley. That's quite enough reading for today." Who could possibly want to hear what Mr. Knightley thinks? If Claudius wanted to read the opinions of an insufferably sanctimonious man, he'd be reading Philo Vance.