Story time: A walk in the park

“I came here first…" "No, I came here long before you did." Alfred Bates, the famous detective couldn't stop overhearing the shouts from a nearby bench in the local park. He moved towards the source of the debate and saw a crowd gathered there. "Aaah, here you are Mr Bates," Mr Bollinger of the local post office said. "I can't make head or tail of Mr John's and Mr Abbot's fight. Please help me since they are disturbing us." "Mr Bollinger, perhaps you could assist me by summoning the guard at the gate. I would need his assistance," Bates replies. "Why?" asks the audience, as Mr Bollinger runs away. "Because Mr Abbot and Mr John are not alone in this fight, they have another ally," Bates says. "A junior one if I must say!" At this moment Bates puts his hand behind his back and grabs the arm of a kid who was unsuccessfully trying to pick his pocket. "Never try to rob a policeman of his belongings my friend. We have an extra pair of eyes in the back of our heads."At this moment, the shouting died down and Mr John and Mr Abbot tried to run. The guard caught them and brought them to Mr Bates. "How did you know they were troublemakers and not genuine walkers in the park?" Mr Bollinger asks. "Their shoes told me." "How?" "Take a look at their shoes," Bates explains. "They are brand new jogging shoes. No one around us has brand new shoes because a walk in the park is a dirty business. We all have dirt on our shoes which makes these two more visible to my eyes!""But how did you know they were shouting for no reason?" Mr Bollinger puts another puzzling question. "Because I came here long before they did," Bates continues. "There was an old lady sitting on the bench and since they couldn't move me away — as I seemed a threat — they scared the poor lady away to set the scene for their pick-nic!" "And the kid?" "Oh, he is Mr Abbot's son," Bates concludes. "In fact it was his pick pocket genius that made them go for this plan. If you check their pockets, you would find bank notes from their last robbery which happened this morning. That will give the police enough to charge them." "We would have gotten away had you not been here mister!" Mr Abbot says as he is taken away. "You might have but surely you wouldn't have succeeded. Because… for every robber there is an anti-robber nearby!" Bates says as he goes back to his bench.