BERWYN, Ill. (WLS) -- Berwyn police are warning the public about a potential flash mob at the North Riverside Park Mall Saturday.Police said there have been some posts on social media and acts of violence in past flash mobs at the west surburban mall.There will be extra security in and around the mall.Police are also warning property owners in neighboring communities to be on the lookout once the flash mob leaves the mall.Police are asking residents to make sure their homes, garages and vehicles are locked and secured, and if an unruly group is present when you are attempting to exit your vehicle, you can request an escort from your vehicle to your door by calling police at 708-795-5600.