violence. >>> cher i hill police are stepping up patrols to prevent flash mobs from popping up in shopping center. several malls around the country have been targeted in recent days, "eyewitness news" reportser greg argos is live in cherry hill with more on that police effort, greg. >> reporter: police are stepping up those visible patrols all throughout the mall area, in fact, in the past 30 minutes, we have seen two different people pulled over by cherry hill police in the cherry hill mall parking lot but inside both uniformed and ununiform officers, under cover officers are patrolling as well. >> we have mark, unmark officers assign to the mall, doing corrective patrols and the unmarked officers are inside of the mall and with the hopes that they will be inside there and if they see thinking unusual we will get a jump on it. >> reporter: report after tuesday night's incident at philadelphia mills mall in the northeast where through snap chat 200 teenagers showed up at the mall, a...