Lavengro by George Borrow

A few days after the occurrence of what is recorded in the last chapter, as I was wandering in the City, chance directed my footsteps to an alley leading from one narrow street to another in the neighbourhood of Cheapside. Just before I reached the mouth of the alley, a man in a greatcoat, closely followed by another, passed it; and, at the moment in which they were passing, I observed the man behind snatch something from the pocket of the other; whereupon, darting into the street, I seized the hindermost man by the collar, crying at the same time to the other, "My good friend, this person has just picked your pocket."

The individual whom I addressed, turning round with a start, glanced at me, and then at the person whom I held. London is the place for strange rencounters. It appeared to me that I recognised both individuals -- the man whose pocket had been picked and the other; the latter now began to struggle violently; "I have picked no one's pocket," said he. "Rascal," said the other, "you have got my pocketbook in your bosom. " "No, I have not," said the other; and struggling more violently than before, the pocketbook dropped from his bosom upon the ground.