In absence of a clarification this trope has been merged into Ten Little Murder Victims. I chose that as the primary title because Whack A Mole could also be construed to mean the actual game of Whack A Mole, while Ten Little Murder Victims is a bit more discrete.

Also, I'm utterly puzzled how even those these tropes were pretty much the exact same thing there was almost no overlap between the two. It's like half the wiki was using one term and the other half the other and never the twain did meet.