Mr. Monk is the Best Man - S8-E13
Character mistake: At the end, after Stephanie fired the gun, Captain Stottlemeyer shows her the gun's magazine but calls it a "clip." A police captain like Leland would know the difference between a clip and a magazine and would use the right word.
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.