How does Emilia expose Iago’s plot in the final scene of Verdi’s Otello?

In the final scene of Giuseppe Verdi’s Otello, Emilia exposes Iago’s treachery by revealing the truth about the handkerchief that Otello used as "proof" of Desdemona’s infidelity.

After Otello kills Desdemona and justifies his actions by citing the handkerchief, Emilia—who is Iago’s wife—boldly intervenes. She explains to the group that she was the one who found the handkerchief and gave it to Iago, thereby dismantling the false evidence he had used to manipulate the general. Her testimony is further corroborated when Montano arrives and announces that the dying Roderigo has confessed to Iago’s entire plot.1