Mr. Monk Takes Manhattan - S3-E1
Warrick Tennyson: You were the husband?
Adrian Monk: I am the husband.
Warrick Tennyson: Forgive me.
Adrian Monk: Forgive you? This is me...turning off your morphine. [Turns off morphine. Long pause. Monk covers his eyes and begins to cry.] And this is Trudy, the woman you killed...turning it back on. [Turns on morphine].
Answer: Notice also that in the opening credits scene when he is touching parking meters her also wipes his hand on his clothes each time he does it.