March 21, 2026

What are the Fundamental Concepts of Criminal Proceedings?

In this article, we aim to explain the basic concepts frequently encountered and often confused during the criminal trial process in a brief, understandable, and systematic way. In practice, individuals seek answers to questions such as "what is the difference between a suspect and a defendant?", "what is defense counsel?", and "what is an indictment?".

Correct understanding of concepts used in criminal trials is of great importance for healthy tracking of the process. In this context, the most common basic concepts encountered in criminal trials are addressed.

1. What is a Suspect?

A suspect is a person about whom there is a suspicion based on concrete facts that they have committed a crime. This title is used in the investigation stage of criminal proceedings. In other words, the person is not yet being tried; only an investigation is being conducted about them. The suspect has important rights such as the right to remain silent, the right to request a lawyer, and the right to receive legal aid while giving a statement at this stage.

2. What is a Defendant?

A defendant is a person against whom a criminal case has been opened with the acceptance of the indictment prepared by the public prosecutor. At this stage, the person is now being tried and the title “suspect” changes to “defendant”. The defendant has the right to use the right of defense, to present evidence, and to answer the accusations directed at them throughout the trial.

3. What is a Victim?

A victim is the person who directly suffers harm from the crime committed. This harm can be physical, economic, or moral. Protecting the victim and compensating for their harm is an important goal in criminal proceedings.

4. What is a Participant (Intervenor)?

A participant is the title the victim gains by actively participating in the criminal case. When the victim applies to the court and requests to participate in the case, they now take the title of “participant” and can participate in the trial process more effectively.

5. What is Defense Counsel?

Defense counsel is the lawyer of the suspect or defendant in criminal proceedings. Defense counsel:

  • Represents the defense.

                      * Ensures the protection of legal rights.
                      * Contributes to the conduct of the process in accordance with the procedure.
    
                  

In some cases (for example, in serious crimes), it is mandatory to have a defense counsel.

A legal representative is the lawyer of the victim or participant. The representative protects the victim’s rights, conveys their requests to the court, and follows the process on their behalf. In this respect, the representative is in a position close to the prosecution side, unlike the defense counsel.

7. What is a Public Prosecutor?

A public prosecutor is a judiciary member who acts on behalf of the public in criminal proceedings and is tasked with investigating crimes. The prosecutor:

  • Conducts the investigation.

                      * Collects evidence.
                      * Issues an indictment if necessary.
                      * Represents the prosecution in court.
    
                  

8. What is a Judge?

A judge is the person who decides independently and impartially in criminal proceedings. The judge:

  • Leads the trial.

                      * Evaluates the evidence.
                      * Renders the final decision.
    
                  

9. What is an Investigation?

Investigation is the first stage carried out by the public prosecutor after the suspicion of a crime emerges. The aim at this stage is to reveal whether the crime was committed and by whom it was committed.

10. What is a Prosecution (Trial)?

Prosecution is the trial process starting with the acceptance of the indictment and carried out by the court. At this stage, the evidence is now discussed before the court and a decision is made.

11. What is an Indictment?

An indictment is the document prepared by the prosecutor if they reach a conviction that a crime has been committed, and which starts the criminal trial. An indictment includes:

  • Description of the crime

                      * Summary of the event
                      * Evidence
                      * Identity of the defendant
    
                  

12. What is Evidence?

Evidence is any information and finding used to reveal whether an event occurred. It is of great importance in criminal proceedings that evidence is obtained in accordance with the law.

13. What is a Witness?

A witness is the person who has information about the event and conveys this information to the court. Witness testimonies are an important type of evidence in criminal proceedings.

14. What is an Expert?

An expert is the person who helps the court in technical or specialized matters. For example, forensic medicine reports and technical examinations are done through an expert.

15. What is Custody?

Custody is the temporary restriction of the suspect’s liberty within the scope of the investigation. This measure is applied for the purpose of collecting evidence and conducting the investigation healthily.

16. What is Detention (Arrest)?

Detention is the deprivation of the suspect’s or defendant’s liberty by a court decision in the presence of strong suspicion of crime and certain conditions. Detention is an exceptional protective measure.

17. What are Statement and Interrogation?

Statement is the hearing of the suspect at the prosecution or law enforcement. Interrogation is the hearing of the defendant before the court.

18. What is a Judgment?

A judgment is the decision the court makes at the end of the trial. This decision determines whether the defendant is guilty.

19. What is an Acquittal?

An acquittal is the determination by the court that the defendant is innocent. In this case, no penalty is given to the defendant.

20. What is a Conviction?

A conviction is finding it fixed that the defendant committed the crime and punishing them.

21. What is HAGB?

HAGB is the postponement of the announcement of the verdict despite a judgment being established about the defendant. If the obligations are complied with within a certain period, the case can close without producing results. It stands for “Postponement of the Announcement of the Verdict”.

22. What is an Appeal?

An appeal is the examination of the first instance court decisions by a higher court from both legal and factual aspects.

23. What is Cassation?

Cassation is the examination of the decision by the Court of Cassation only in terms of compliance with the law.

Importance of Concepts in Criminal Proceedings

A correct understanding of these concepts used in criminal proceedings is of great importance for the correct interpretation of the process. In particular, the suspect-defendant distinction, defense counsel-legal representative difference, and investigation-prosecution separation are frequently confused in practice.

The information on this page is prepared for general awareness purposes. Concepts used in criminal proceedings may produce different legal results according to the characteristics of the concrete case. A correct understanding of the concepts regarding the criminal trial process is important to avoid loss of rights.

The information on this page is prepared for general information purposes. Concepts used in criminal trials may yield different legal outcomes depending on the characteristics of the concrete case. In order to correctly understand the concepts related to the criminal trial process and avoid loss of rights, it is important to obtain legal support suitable for your concrete situation.

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