A longtime political operative at the center of the investigation into former Chicago Ald. Daniel Solis pleaded not guilty Friday in alleged schemes to influence a massive Chicago Public Schools janitorial contact and solicit campaign cash for Solis. Roberto Caldero, 68, was charged last week in an eight-count indictment with wire fraud, federal program bribery and facilitating bribery, allegedly in a plan to exchange the contributions for the aldermanâs help renaming a street and city park. He pleaded not guilty during a telephonic arraignment before U.S. District Judge Steven Seeger. The most serious charges call for up to 20 years in prison if convicted.