In the American justice system, the prosecutor ultimately decides whether to prosecute someone and for what offense or offenses.
When the police make an arrest, the arrest is a mere accusation of a crime. The standard of proof required to make an arrest is whether there is probable cause that someone has committed a crime.
Probable cause is a low standard of proof. It is even less than the civil standard of proof, which is a preponderance of the evidence. As a result, a police officer need not even have proof that it is more likely than not that a crime has occurred.
For a police officer to have probable cause to make an arrest, he or she must reasonably believe “a man of reasonable caution that a crime is being committed.” Brinegar v. United States 338 U.S. 160 (1949).
The prosecution cannot rely on mere probable cause. They have to present proof, beyond a reasonable doubt, to a jury that a crime has occurred.
As a result, sometimes the State must dismiss the case of someone they believe is likely guilty when they have insufficient evidence to prove guilt beyond all reasonable doubt. Even though a police officer had probable cause to make an arrest, the case cannot be sufficiently proved to get a conviction in court.
In other circumstances, the State's attorney may decide to change a person's charges. In Georgia, the District Attorney, in felony cases, or the Solicitor General, in misdemeanor cases, has the authority to amend any criminal charge. Additionally, the prosecutor can add charges for which a person had never even been arrested.
Moral and Ethical Responsibility of Prosecutors:
The power to prosecute is awesome. I remember thinking so when I was a young prosecutor in North Georgia.
It is important for prosecutors to remember that winning their cases is not their first duty. The duty of a prosecutor is to justice and fairness. It is not to win their cases at all cost. Most prosecutors fully understand their ethical role.
However, a few (usually young) prosecutors forget that it is far better to let a guilty person free than to allow an innocent person to be found guilty.
As a society, we all focus far too much on winning. As defense attorneys, we have a clear duty to our clients. I would remind young prosecutors that your duty is to protect the rights of even the accused. Only then will our prosecutors make the right decision whether to prosecute.