Final answer:
Ludovico exposes Iago's wickedness through a testimony where a corpse, revived momentarily by an Egyptian prophet, accuses his wife of murder for her lover's sake, leading to the uncovering of Iago's deceitful and treacherous character.
Step-by-step explanation:
The evidence Ludovico produces that incriminates Iago is a riveting piece of narrative in which a young man who has apparently died comes back to life momentarily through the rites performed by an Egyptian prophet. Upon revival, the young man accuses his new wife of poisoning him to indulge in a romantic affair with another and to gain control over his estate. The twist in the tale is the reveal of a man in the crowd who had been guarding the corpse. He realizes he has been disfigured as a result of magic used by witches who intended to mutilate the dead body, but instead, due to the name confusion and magic-induced sleep, mutilated him.
Ludovico's evidence takes the form of this detailed and personal account, implicating Iago in acts of deceit and wickedness. It is this testimony of deceit, unfathomable manipulations, and sorcery that brings to light Iago's treacherous character. Ludovico's revelation shakes the confidence of those around, exposing Iago's dishonorable actions and thereby incriminating him.