The criminal justice system is the set of agencies and processes established by governments to control crime and impose penalties on those who violate laws. There is no single criminal justice system in the United States but rather many similar, individual systems. How the criminal justice system works in each area depends on the jurisdiction that is in charge: city, county, state, federal or tribal government or military installation. Different jurisdictions have different laws, agencies, and ways of managing criminal justice processes. The main systems are State criminal justice systems handle crimes committed within their state boundaries and the federal criminal justice system handles crimes committed on federal property or in more than one state. Most criminal justice systems have five components-law enforcement, prosecution, defense attorneys, courts, and corrections, each playing a key role in the criminal justice process. Law enforcement officers take reports for crimes that happen in their areas. Officers investigate crimes and gather and protect evidence. Law enforcement officers may arrest offenders, give testimony during the court process, and conduct follow-up investigations if needed. Prosecutors are lawyers who represent the state or federal government (not the victim) throughout the court process-from the first appearance of the accused in court until the accused is acquitted or sentenced. Prosecutors review the evidence brought to them by law enforcement to decide whether to file charges or drop the case. Prosecutors present evidence in court, question witnesses, and decide (at any point after charges have been filed) whether to negotiate plea bargains with defendants. They have great discretion, or freedom, to make choices about how to prosecute the case. Victims may contact the prosecutor's office to find out which prosecutor is in charge of their case, to inform the prosecutor if the defense attorney has contacted the victim, and to seek other information about the case. Defense attorneys defend the accused against the government's case. They are ether hired by the defendant or (for defendants who cannot afford an attorney) they are assigned by the court. While the prosecutor represents the state, the defense attorney represents the defendant. Courts are run by judges, whose role is to make sure the law is followed and oversee what happens in court. They decide whether to release offenders before the trial. Judges accept or reject plea agreements, oversee trials, and sentence convicted offenders. Correction officers supervise convicted offenders when they are in jail, in prison, or in the community on probation or parole. In some communities, corrections officers prepare pre-sentencing reports with extensive background information about the offender to help judges decide sentences. The job of corrections officers is to make sure the facilities that hold offenders are secure and safe. They oversee the day-to-day custody of inmates. They also oversee the release processes for inmates and sometimes notify victims of changes in the offender's status.