I found it in my chamber:
And he himself confess’d but even now
That there he dropp’d it for a special purpose
Which wrought to his desire.

– William Shakespeare

Othello, Act 5, Scene 2. Asked by Othello how he came by Desdemona’s handkerchief, Cassio reveals Iago’s lies and exposes his true nature. Cassio says that he found the handkerchief in his chamber, dropped there by Iago dropped as part of his special plan.