What a total tool bag Iago was. He sets both Desdemona and Cassio up by getting his wife to pick up a discarded handkerchief Desdemona accidentally dropped. He had it planted as so that Othello would believe that the very personal handkerchief he gave her as a present, would prove that she was having an affair.

Othello thinking she has had an affair with Cassio kills her. But then Iago’s wife tells the truth that she, not Cassio was the one who picked up the handkerchief and he, Othello had murdered his wife based on the lie of Iago.