Place it immediately after the false statement, as the payoff at the end of the setup. Build tension first with Sudden Suspense, then cut straight to this accusation, and follow it with Oh My God Wow for the stunned reaction that closes the scene.
About this sound
This is a short German voice clip, about three and a half seconds long, in which a speaker angrily calls out a lie and ends with the insult Dreckssau. The delivery is heated, blunt and confrontational, with the emphasis landing hard on the accusation. It feels like catching someone red-handed and refusing to let the claim stand.