in the produce aisle, the man in the white shirt gets the attention of the clerk. now the clerk's back is turned, his partner in the row behind him swoops in as the woman in the hat looks away from her cart to pick the perfect apple, he picks up her wallet. surviellance videos to kgtv hoping they would lead to an arrest. theft rings run by sticky-finger crooks are making a killing. in philadelphia, investigators say this group has perfected the crime. this man sits directly behind his victim, hidden by his jacket he reaches right inside of her purse hanging on the chair. >> the thieves analyze you very well, watching for the weakest victim. >> reporter: bob arnot is a master pickpocket who advises law enforcement on how to catch the crooks. he and his wife bambi acting as the decoy show me how it is done. the woman at this table is so busy talking she has no idea what is going on behind her. >> did you take my wallet? >> did you have any idea what he