Place it at the exact frame the secret is shown, then follow it with the dramatic dun dun dun sound effect for a second accusation beat, or end on a vine boom sound effect if the reveal is meant as a joke.
About this sound
This is a four-second sci-fi stinger played when a player's role is shown at the start of a match. It feels tense and quietly ominous, building instant suspicion around whoever is on screen. It comes from Among Us, the multiplayer social deduction game by Innersloth first released in 2018.