What is a criminal trial and how does it unfold?
The trial is the culminating moment of the criminal process. It is the act in which all the pieces of the process come together: the investigation carried out during the investigative phase, the charges formulated in the intermediate phase, and the defence articulated by the accused converge before a court that must hear all parties, assess the evidence presented, and rule on the guilt or innocence of the accused through a judgment.
Despite its importance, the trial is one of the phases of criminal proceedings that generates the most misunderstanding among non-lawyers. The image many people have of a trial is distorted by television series and films, which portray it as a dramatic spectacle full of last-minute revelations and decisive arguments. The reality is far more structured, more technical, and, precisely for that reason, more demanding for anyone who wants to face it with real guarantees of success.
In this article, we explain in full what a criminal trial is, what its governing principles are, how it unfolds step by step, what happens at each stage, and what role each party plays, with particular attention to the rights of the accused and the importance of a well-prepared defence.
What is a criminal trial?
A criminal trial is the central and decisive phase of the criminal process in which a court —composed of one or more judges depending on the seriousness of the offence— hears the parties, examines the evidence, and decides whether the accused is guilty or innocent of the offence charged. It is the stage in which the presumption of innocence is tested: the prosecution must prove, beyond reasonable doubt, that the accused committed the alleged acts. If it fails to do so, the court must acquit.
Unlike the investigative phase —which is predominantly written and confidential, where the judge investigates relatively discreetly— the trial is governed by radically different principles. It is public, oral, immediate, and adversarial: public because any citizen may attend unless the court decides otherwise for justified reasons; oral because arguments, testimonies, and evidence are presented verbally before the court; immediate because the court deciding the case directly witnesses the evidence being presented; and adversarial because prosecution and defence have equal opportunities to present their version and challenge the opposing one.
The trial is neither the beginning of the process nor its immediate conclusion: it is the point where all previous stages converge and from which the judgment emerges. Everything built during the investigation —evidence gathered, statements taken, reports prepared— forms the basis of what happens in the courtroom.
The principles governing the trial
To understand how a trial works, it is essential to know the procedural principles that govern it, as they explain why it unfolds as it does and what guarantees protect the accused:
Principle of orality
Everything that happens in the trial is expressed verbally and directly before the court. Statements, examinations, expert reports, and arguments are presented live, allowing the court to observe not only what is said but how it is said. Written documents gathered during the investigation may be introduced, but their evidentiary value depends on how they are presented and challenged.
Principle of publicity
As a general rule, the trial is open to the public. Anyone may attend as a spectator, and the media may report on what occurs. This ensures transparency in the justice system. However, the court may order closed proceedings when publicity could affect fundamental rights, such as the victim’s privacy or the best interests of a minor.
Principle of immediacy
The court that delivers the judgment is the same one that directly witnesses the evidence. This means the judges deciding the case have personally heard the witnesses, observed their behaviour, and assessed credibility in real time. This ensures quality in the evaluation of evidence.
Principle of adversarial proceedings
No evidence can be considered unless it has been challenged by the opposing party. The defence can question prosecution witnesses, challenge expert reports, and present its own version. Likewise, the prosecution may cross-examine defence witnesses.
How the trial unfolds step by step
The trial follows a defined structure:
1. Constitution of the court and preliminary issues
The trial begins with the formal constitution of the court and verification that all parties are present. Preliminary issues may be raised —such as lack of jurisdiction, violation of fundamental rights, statute of limitations, or res judicata. If upheld, the trial may end at this stage.
2. Reading of prosecution and defence statements
The parties confirm or read their submissions and may modify them. The defence may also accept the charges, ending the trial without evidence being presented.
3. Taking of evidence
This is the core phase. The accused may testify or remain silent. Witnesses and experts are examined and cross-examined. Documents are introduced.
4. Closing arguments
Each party summarises its case, evaluates the evidence, and requests conviction or acquittal.
5. Final statement of the accused
The accused has the right to speak last, personally and without interruption.
6. Deliberation and judgment
The court deliberates and issues a reasoned judgment, either convicting or acquitting.
Who participates and their roles
The court directs proceedings and issues judgment.
The public prosecutor represents the State.
Private prosecution represents the victim.
The accused exercises defence rights.
The defence lawyer protects the accused.
Witnesses and experts provide evidence.
Why preparation is decisive
The trial is not improvised. Every decision must be planned as part of a defence strategy developed from the investigative phase through to trial preparation.
Frequently asked questions
Is the accused required to attend? Generally yes, except in minor cases.
Can the trial be suspended? Yes, for justified reasons.
Can the victim participate? Yes, as a private prosecutor or witness.
What if the accused confesses? It is evidence but not automatically decisive.
How long does the judgment take? Usually 5–10 working days, though it may take longer in complex cases.
