At the end of the tragedy of julius caesar, what convinces brutus that he should not have killed caesar?

At the end of Shakespeare's The Tragedy of Julius Caesar, Brutus comes to regret taking part in the murder of Caesar because he learns that the evidence concerning Caesar's attempts to usurp political power was, in fact, false. He realizes that if he hadn't been faced with this false evidence, then he would not have taken part in Caesar's murder.