A more thorough explanation:

A state's attorney is a lawyer who is elected or appointed by local government officials to represent the state in criminal cases. They are responsible for presenting the case against individuals suspected of violating the law, initiating and directing further criminal investigations, deciding what criminal charges to file, guiding and recommending sentences for offenders, and participating in grand jury proceedings.

For example, if someone is accused of committing a crime, the state's attorney will be the one who brings charges against them and represents the state in court. They will also work with law enforcement to investigate the case and gather evidence.

State's attorneys can be appointed by the chief executive of the jurisdiction or elected by local voters. They are also known as district attorneys, public prosecutors, or prosecuting attorneys.

In the federal system, the equivalent of a district attorney is a United States Attorney, who is appointed by the President.