Chicago News was a newspaper in Chicago, Illinois in 1927. Marty McFly read the headline that mentioned a mob shootout where rival mobs vowed to retaliate. This gave him the idea to stage a police raid of the speakeasy owned by mob boss Arnie "Eggs" Benedict.
He used his sound effects key ring to simulate gun fire, which led the gang to believe that Marty, posing as a mobster named "Zipper" McFly, defeated the police. He tells them to let his cousin Jim McFly out of the gang, and warned if they did not, the McFly gang would be back to make a few omelettes.