In 3.5, Richard has succeeded in getting rid of Hastings by getting the Mayor to believe the false stories about him. Richard pretends great indignation saying he had been duped by Hastings and feigning great sorrow at his alleged treachery:  

"So dear I loved the man that I must weep. / I took him for the plainest harmelss creature / That breathed upon the earth, a Christian, / Made him my book wherein my soul recorded / The history of all her secert thoughts. / ... / HYe lived from all attainture of suspect."

Of course, it is evil to falsely accuse someone. However, Richard's ability to manipulate others seemingly knows no bounds and demonstrates his cunning.

The line from 2.1.60 to the end of the scene, Richard again shows his cleverness by casting doubt the motives of Hastings.  He asks the King, "Marked you not how the guilty kindred of the Queen / Looked pale when they did hear of Clarence' death? "

Richard of Glouchester may be the greatest manipulator of all time.  He hones in on the weaknesses of others and uses them to futher his own plans, no matter who he hurts, or kills, along the way.