CHENNAI, June 17: The Chennai City Police Commissioner V K Rajagopalan has issued memos to nine police officers seeking explanation to the increasing instances of petty rowdyism in the city, leading to damage of property, during the past few months. While during one incident, two groups clashed over the route for a funeral procession, ending in damage to five autos and two mopeds, in another, petrol bombs were thrown into a TTC bus stand near the Esplanade police station, here.