Those who prosecute persons accused of violating state criminal statutes are commonly known as district attorneys. In most states they are elected county officials; however, in a few states they are appointed. The district attorney's office usually employs a number of assistants who do most of the actual trial work. Most of these assistant district attorneys are recent graduates of law school, who gain valuable trial experience in these positions. Many later enter private practice, often as criminal defense attorneys. Others will seek to become district attorneys or judges after a few years.

The district attorney's office has a great deal of discretion in the handling of cases. Given budget and personnel constraints, not all cases can be afforded the same amount of time and attention. Therefore, some cases are dismissed, others are not prosecuted, and still others are prosecuted vigorously in court. Most cases, however, are subject to plea bargaining. This means that the district attorney's office agrees to accept the defendant's plea of guilty to a reduced charge or to drop some charges against the defendant in exchange for pleas of guilty to others.