Through the decision to prosecute and the description of the offence that the prosecutor gives, he/she sets the framework for the criminal action.
During the course of the trial, the prosecutor is a party in the action. The prosecutor asserts during the trial that a certain person has committed a certain offence, after which the court judges whether or not this is in fact the case.
The task of the prosecutor during the trial is to prove that the offence has been committed. If the suspect denies committing the offence, the prosecutor has to present so much evidence that it is deemed proven without reasonable doubt that the assertions are in fact true. The prosecutor must, however, be objective, and shall also present any evidence that is in the suspect’s favour.
If any new information is presented during the course of the trial that changes the case, the prosecutor may need to reconsider the question of prosecution. In exceptional cases the charges may be dropped during the course of an ongoing trial.
The prosecutor plays a very active role in court.