Othello - Act 3

This act creates even more suspense to the play because Iago's plan keeps working out perfectly.  He plants the seed into Othello's mind the idea that Desdemona could be cheating on him.  Othello is worrying about it for the rest of the act trying to figure out if she really is cheating on him.  Throughout the act, the suspense keeps increasing to find out when Othello is going to call out Desdemona for cheating on him.  Iago's deception continues when he tells lies about what Cassio said in his sleep.  He said he heard Cassio say, "Sweet Desdemona, let us be wary, let us hide our loves."  Cassio did not say this, but Iago is trying to give some evidence to Othello that his opinion is true.  Othello has the final straw and orders Cassio to be dead within three days.  I am wondering how Iago plans to do this.  If he is considered Cassio's friend, then will he get someone else to kill Cassio or will he do it himself?  After Iago receives Desdemona's handkerchief, he decides to use it against her to complete the assumptions that were placed in Othello's mind.