Alright, so here's why I'm suspecting LM.
He awkwardly tries to extract an admission from me for lie detect purposes, presumably. I didn't comply because I didn't trust him, and I'm glad I didn't, because upon catching up:
The host makes it explicitly clear that Ratchet claiming town and being Lie Detected is what led to this kill.
Now Lord Melkor has admitted he has a "reason" for his request, that he didn't specify. Mind you, I already dropped LM as a suspect at this point in time.