I watched "The Guardian of Time's Sword" episode recently and thought of a similar case.
Here's a summary of what happens in that episode;
So here's what I though of, dunno if this was already happened in the series;
So these two may seem like different cases but when you compare them together they are pretty much the same plot. Kill someone in crowd in the dark, and force the evidence out of the window/door with some kind of mechanism. Heck, the party could even take place outside where the only lights around in that area belong to the house the party is at so nobody will see anything when there's black out. And the sky is cloudy so no moonlight either.
What do you think, I believe there should be cases similar in this way.