I'm feeling a bit awkward that I can't give credit where it's due, but the Reddit post I'd bookmarked has been deleted. I still have the commands, though, which are as follows:
for i,v in ipairs(Osi.DB_CRIME_GuardKiller:Get(nil,nil,nil,nil,nil,nil,nil)) do CrimeSuspend(v[7]) print(v[7]) end
Osi.RemoveStatus(GetHostCharacter(), "GB_GUARDKILLER")
Osi.DB_CRIME_GuardKiller:Delete(nil, nil, nil, nil, nil, nil, nil)
Don't forget to press return before pasting the commands as it appears the console starts in logging mode and doesn't start accepting commands until you've already typed something. Occasionally this command set doesn't completely clear the crime flag it for the faction in question but it'll prevent it from continuing to haunt you in future encounters elsewhere.
FWIW, the witness I had at the Shrine of Selûne (goblin camp) was Sazza, and in Moonrise Tower it was Roah, ironically; she'll witness you even if you're sneaking with solid objects in the way, so cast a cloud of darkness on her first if you want to keep her alive but not report you.
