Chicago's new solution to crime: Signs on the CTA that say violence is illegal. "We are hoping to deter crime and to encourage people to come forward if they are witnesses of crime." The Cook County State's Attorney's Office will prosecute and seek pretrial detention for all violent offenses on public transit." Participants include the Cook County State's Attorney's Office, Chicago Police Department, CTA, Cook County Sheriff's Office, Metra and Pace. The state's attorney's office also created an internal CTA task force focused on prosecuting transit-related crime in Chicago.