An SK with a day kill isn't implausible. What is implausible is that it would be an SK witha day kill that gets publically announced to the thread by the user having to post it and tag the host to process it. That makes 0 sense. It would be hidden. Could argue it would usually be hidden and the announcing of it was performative, but then, what would we think when we see more day kills that aren't announced by the player? It simply does not stand up to reason.
If they're Indie, it would be something g that needs to kill roles or whatever. Not a straight up Serial killer.