Iago has succeeded in making Othello very suspicious of his wife and her relationship with Cassio. However, he is not completely convinced of her infidelity, and he begins to become suspicious of Iago himself. In Act 3, Scene 3, he turns on Iago and says: "Villain, be sure thou prove my love a whore! / Be sure of it. Give me the ocular proof, / Or, by the worth of mine eternal soul, / Thou hadst been better have been born a dog / Than answer my waked wrath!" Iago feels in deadly peril. He contrives to get a handkerchief which Othello valued highly and gave to Desdemona, who accidentally lost it. Iago manages to have Cassio find it and to give it to his whore Bianca, who returns it contemptuously to Cassio while Othello and Iago are spying on them. This is the "ocular proof" Othello demanded, since the handkerchief is a nearly sacred object to him and he is convinced that Desdemona gave it to Cassio as a token of love. Othello's wrath causes him to murder the wife he still loves even while he is strangling her.