to summarize (sorry for repetition from other post but i wanted everything in one post):
1. everyone keeps pointing out how similar archie and jason looked and were. they had more in common than sports; they were both tutored by ms grundy (pause for vom), they were both at the river. they both had red hair. archie was the intended target, and the killer is grundy’s husband.
why? like i’ve said, i hated that plot to high hell but grundy did seem to be really genuinely afraid of him (assuming that was the truth), afraid that he’d do something terrible to her. if it was the truth and that’s why she changed her identity, then ostensibly he’s real dangerous.
2. edit: it would be a huge realization for archie that he was a victim. he really assumed he was safe with grundy. that was actually something he reiterated many times—he knew what he was doing, he was safe, it was all his choice. but it wasn’t, right? he was manipulated by her, and completely preyed upon.
i think it would help archie realize that he was a victim and come to terms with the way she abused him emotionally as well as physically.
the original point didn’t come off right, so i edited it here to clarify.
it also makes sense because the only other people with motives to torture a kid for a week seemed to acquit themselves in the recent episode
polly has an alibi, the coopers genuinely seem like they didn’t do it (plus it’d be way too obvious), and the blossoms wouldn’t torture jason
3. we’re halfway through the season; if we haven’t met the killer yet i’d be surprised. if i’ve learned anything by doing meta and theories is how to structure pacing. the killer has to strike again, and it has to be someone we’ve seen; someone who’s a recurring character. all of the main characters seem innocent.
so back to my first point, who’s the only lone character with those connections to grundy and archie, re: music?
professor oscar castillo.
4. remember in 1x05 where he stiffened at the name “grundy” ? he said “the music teacher who left?” remember when he turned away and said something weird about the connection she clearly had with archie? how he clearly hated archie on sight? he’s grundy’s husband.
the actor has been booked for a recurring role [x], and i’ll bet he was at the river that day, he thought jason was archie, but after he’d realized it wasn’t archie he couldn’t let jason leave. so he tortured him for information on grundy and archie and eventually shot jason, but now has to wait for the right time to strike again.