Not sure if either of these would work for you, but I'm looking to do a few short threads so here it goes:
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So
Lochlann has killed some people on the island, and he only remembers killing one of them. Emy's character, Adrian Grimm, mysteriously disappeared in July and it was Lochlann's fault. He doesn't remember this one at all.
The death of Kyros's Zelda Winters is also Lochlann's fault.
It would be really really hard to track down or prove either of these, but since Lochlann has a sealed record with the school and there's rumors about his past, some pressure on Lochlann would be really great.
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Another option might be
Cabel Sokot. Cabel is my drug-dealing alchemist. He's never intentionally killed someone, but people have dicked around with Cabel's drugs and died as a result. Cabel would probably have more run ins with the law.