Criminal procedure is one of the branches of law where public power is most intensely felt, striving to realize the ideal of reaching the material truth and establishing justice. This process, by its nature, is built upon a delicate balance, encompassing on one hand the legitimate interest of society in the clarification of crime, and on the other, the fundamental rights and freedoms of the individual under criminal suspicion, which are protected by the constitution. One of the most critical points in this balance is constituted by the protective measures that directly interfere with personal liberty, which are resorted to in order to ensure the participation of the suspect or defendant in the investigation and prosecution processes.

The Turkish Code of Criminal Procedure (“CCP”) envisages a series of mechanisms to secure this mandatory participation. These mechanisms exhibit a graduated structure, progressing from the least to the most severe intervention. While the process begins with the institution of a "summons" (invitation), which relies on the individual's consent and obligation, in the event of non-compliance with this summons or the fulfillment of other legal conditions, more intrusive measures that restrict individual liberty, such as "compulsory appearance," "arrest," and "detention," come into play.

Although these three institutions compulsory appearance, arrest, and detention are often confused with one another or perceived as continuations of each other, they are, in fact, independent and distinct protective measures, each possessing its own unique legal nature, conditions of application, causes, and consequences, and varying in severity. The purpose of this text is to conduct an in-depth analysis of these three fundamental institutions of criminal procedure, going beyond a mere literal repetition of the statutory texts, within the framework of their underlying legal philosophy, the objectives they serve, and the nuances between them. In particular, it will focus on how the principle of "proportionality," an indispensable principle of the modern state of law, should shape the hierarchy among these measures and what consequences the violation of this principle in practice may entail. This analysis, while outlining the theoretical framework of the measures, also aims to shed light on the problems encountered in their application.

1. Compulsory Appearance

For the criminal procedure to progress, the presence of the suspect or defendant at certain procedural acts (such as taking of a statement, interrogation, identification, etc.) is essential. The fundamental rule in our legal system, as stated in Article 145 of the CCP, is to summon these individuals with a duly served "summons." This summons must explicitly state the reason for which the person is being called and that the legal consequence of non-compliance will be "compulsory appearance." This is a civilized approach that demonstrates the state's initial respect for the individual, its expectation of their cooperation, and that the use of force is a last resort.

However, when this summons is not heeded, or in certain exceptional circumstances, the institution of "compulsory appearance" (formerly known as "ihzar müzekkeresi" or writ of forcible appearance) is invoked to prevent the disruption of the proceedings. This measure, regulated in Article 146 of the CCP, is not essentially a deprivation of liberty, but a limited measure that ensures the person is "brought" before the judicial authority for the purpose of carrying out a specific procedural act.

• 1.1. Legal Nature and Conditions of Compulsory Appearance

There are two main scenarios for issuing a compulsory appearance order:

• Case of Non-Compliance with a Summons: The most common situation is when a suspect or defendant who has failed to appear for a statement or interrogation despite a duly served summons has a compulsory appearance order issued against them by the Public Prosecutor, judge, or court that is to conduct the procedure. This is, in its purest form, a sanction developed by the system against the individual's failure to fulfill their obligation.
• Cases Where a Compulsory Appearance Order Can Be Issued Directly: Article 146/1 of the CCP provides an exception for more serious situations. If there are concrete facts that would necessitate a detention order against the suspect or defendant under Article 100 of the CCP, or if sufficient grounds exist for issuing an arrest warrant under Article 98 of the CCP, a compulsory appearance order may be issued directly without sending a summons. This allows for a person to be brought under control with a lighter measure to assess the situation in urgent and grave cases, such as the high probability of evidence tampering or flight.
• 1.2. Distinguishing Features of Compulsory Appearance from Other Measures

The fundamental differences that distinguish compulsory appearance from arrest and detention lie in its lighter and purpose-bound nature:

• Limitation of Purpose: The sole purpose of compulsory appearance is to carry out a specific procedure (statement, interrogation, etc.) before the authority that issued the order (prosecutor, judge, court). The measure ends immediately upon the completion of the procedure. The person is released thereafter unless another measure (e.g., detention) is ordered.
• No Placement in a Holding Cell: A person who is brought by compulsory appearance is not placed and held in a holding cell like an arrested person. They are directly escorted by law enforcement officers to the judicial authority specified in the order. The process must be completed in the shortest possible time. Article 146/4 of the CCP clearly defines this period as “immediately,” and if this is not possible, “at the latest within twenty-four hours,” excluding travel time.
• No Record Creation in GBT/UYAP: A person against whom a compulsory appearance order is issued is not registered in national search systems (General Information Collection - GBT or National Judiciary Informatics System - UYAP), unlike a person for whom an arrest warrant is issued. This means the measure has a much less stigmatizing effect.
• The Principle of Not Using Handcuffs: Perhaps one of the most significant differences lies in the wording of Article 93 of the CCP. This article permits the use of handcuffs only during the transfer of “arrested” or “detained” persons if there are signs of danger of flight or harm to themselves or others. Since a person “brought by compulsory appearance” does not fall into either of these categories, as a rule, they cannot be handcuffed. This is the most concrete indicator that compulsory appearance is legally and factually a lighter protective measure than arrest.

In summary, compulsory appearance is a proportionate and limited tool that enables the authorities responsible for conducting the proceedings to have an uncooperative individual physically present, but only for the duration of a specific procedure.

2. Arrest

Arrest is a much more serious interference with personal liberty compared to compulsory appearance. This measure signifies not merely the transportation of a person from one place to another, but also their temporary and actual restriction of freedom by being placed under the control of the state. The legal framework for arrest appears in two different situations: arrest in flagrante delicto, which can be carried out by anyone, and an arrest warrant based on the decision of judicial authorities.

• 2.1. Types of Arrest and Conditions of Application
• 2.1.1. Arrest in Flagrante Delicto and Similar Cases (CCP Art. 90)

This is the most well-known and emergency-specific form of arrest.

• Authority of Any Person to Arrest: In cases of self-defense or necessity, where a crime is being committed ("in flagrante delicto") or has just been committed and the person is being pursued while the traces, effects, and evidence of the act are upon them, even any citizen has the authority to make an arrest if there is a possibility of flight. This is an exceptional authority aimed at protecting social order.
• Authority of Law Enforcement to Arrest: In addition to the above situation, law enforcement officers may also make a direct arrest when there are grounds requiring a detention order or an arrest warrant and there is a risk in delay, and they are unable to immediately contact the Public Prosecutor or their superiors. This is a critical power aimed at preventing the loss of evidence or the escape of the suspect.
• Immediate Notification of the Public Prosecutor: After such an arrest, the Public Prosecutor is immediately notified, and actions are taken in accordance with their instructions.
• 2.1.2. Arrest upon a Warrant (CCP Art. 98)

This is the type of arrest that occurs at the initiative of the investigation and prosecution authorities and is based on a written order. This is the form of arrest most frequently confused with compulsory appearance and is at the center of the proportionality debate.

• Investigation Phase: During the investigation phase, an "arrest warrant" may be issued by the Peace Criminal Judgeship upon the request of the Public Prosecutor for a suspect who has not appeared despite being duly summoned or who could not be summoned (e.g., address unknown). This warrant is sent to all law enforcement units nationwide, and the suspect's information is entered into systems like GBT/UYAP. The person will now appear as a "wanted person" in any identity check.
• Prosecution Phase: During the prosecution (court) phase, the court may issue an arrest warrant for a fugitive defendant on its own motion (re'sen) or upon the request of the Public Prosecutor.
• Bringing the Person Before a Judge or Court: A person arrested upon a warrant must be brought before the competent judge or court within twenty-four hours at the latest, as per Article 94 of the CCP. If this is not physically possible, their interrogation or statement is taken within the same period via the Sound and Video Information System (SEGBİS) at the courthouse of the place of arrest.
• 2.2. The Proportionality Problem Between Arrest and Compulsory Appearance

When examining the legal texts, it is observed that both Article 146 of the CCP (compulsory appearance) and Article 98 of the CCP (arrest warrant) share a common triggering condition: "failure to appear upon a summons." This situation creates an impression in practice that it grants the prosecutor's office a choice. That is, the prosecutor can either issue a compulsory appearance order for a suspect who disobeys a summons or request an arrest warrant from the Peace Criminal Judgeship.

However, this interpretation disregards the fundamental principles governing criminal procedure, particularly the right to liberty and security of person guaranteed by Articles 13 and 19 of the Constitution and Article 5 of the European Convention on Human Rights, and the principle of "proportionality" in the restriction of this right. The principle of proportionality mandates that if there are multiple means to achieve an objective, the one that interferes the least with rights and freedoms must be chosen.

In this context:

• Suitability: Both compulsory appearance and arrest are “suitable” means for serving the purpose of bringing a suspect before a judicial authority.
• Necessity: This is the critical point. An arrest warrant is a much more severe measure that places the person on a wanted list, has the potential to restrict their freedom for a longer period, allows for the use of handcuffs, and carries the possibility of subsequent detention. Compulsory appearance, on the other hand, is merely a momentary transfer. If the sole purpose is to take a statement, resorting directly to the more severe arrest warrant when the lighter measure of compulsory appearance is available is a clear violation of the “necessity” sub-principle.
• Proportionality (in the narrow sense): There must be a reasonable balance between the individual burden caused by the measure and the public benefit it provides. Issuing an arrest warrant that puts a suspect—whose statement could be obtained through compulsory appearance—into the status of a “wanted person” and potentially causing them to spend a night in a holding cell is a disproportionate intervention.

Therefore, an interpretation consistent with the spirit of the law and fundamental principles requires a sequential use of authority: first, a summons should be issued; if there is no compliance, a compulsory appearance order should be given; and only if the person cannot be reached despite this order or continues to flee, an arrest warrant should be issued as a last resort. Resorting directly to an arrest warrant carries the risk of violating the principle of "proportionality" and, consequently, the right to liberty and security of person.

3. Detention

Detention is a state of deprivation of liberty that begins after the moment of arrest and continues for the periods specified in the law. While arrest is an instantaneous act, detention signifies a process. This institution, regulated in Article 91 of the CCP, underscores that there can be no "pre-emptive detention" in criminal procedure. In other words, a person can only be taken into detention after being arrested and only if certain conditions are met.

• 3.1. Conditions for a Detention Order

The Public Prosecutor may decide not to release an arrested person and order their detention. However, this authority is not absolute or arbitrary. Article 91/2 of the CCP makes it mandatory for two fundamental conditions to exist concurrently for this decision to be made:

• Necessity for the Investigation: The detention measure must be "necessary" for the proper conduct of the investigation. This necessity must be based on concrete grounds, such as the collection of evidence, the danger of the suspect tampering with evidence or exerting pressure on witnesses, the need to reach other suspects, or the time required for complex investigative procedures (identification, crime scene reconstruction, confrontation, etc.). The prosecutor must justify this necessity in their decision.
• Existence of Concrete Evidence Indicating Criminal Suspicion: To resort to a severe measure like detention, more than a simple suspicion is required. It is essential that there is a suspicion based on "concrete evidence" that the person has committed the crime under investigation. This refers to the existence of objective and tangible data, such as a witness statement, a camera recording, or a fingerprint.

Uygulamada, kolluk birimlerinin soruşturma dosyasını savcılığa "ikmalen" (şüpheli getirilmeden, sadece evrak olarak) veya "mevcutlu" (şüpheliyle birlikte) göndermesi usulü, bu prensibin bir yansımasıdır. Her yakalanan kişinin otomatik olarak savcılığa "mevcutlu" getirilip gözaltına alınması gerekmez.

• 3.2. Detention Period and Safeguards

In practice, the procedure of law enforcement units sending the investigation file to the prosecutor's office either "for completion" (without the suspect, only the documents) or "with suspect present" reflects this principle. Not every arrested person needs to be automatically brought "with suspect present" to the prosecutor's office and taken into detention.

4. Conclusion

Compulsory appearance, arrest, and detention are protective measures designed to achieve the objectives of criminal procedure, but each is founded on a different level of severity and legitimacy, and they are separated by sharp distinctions. The correct understanding and application of these institutions are a litmus test of a state of law's respect for fundamental rights and freedoms.

The main conclusions to be drawn from our analysis are as follows:

• A Graduated System: These three measures are not alternatives to one another but are parts of a graduated system built upon each other. The basic rule is to start the process with the least intrusive measure, the summons. If the summons is unsuccessful, the second stage should be the purpose-bound and limited measure of "compulsory appearance." The "arrest warrant" is a "last resort" measure that should be reserved for more severe situations where the compulsory appearance measure has also failed or where the specific legal conditions (such as flight, evidence tampering) are met. Finally, "detention" is a temporary state of deprivation of liberty that can only be resorted to after an arrest and only when there is a concrete necessity for the investigation and the existence of evidence.
• The Central Role of the Principle of Proportionality: Requesting an arrest warrant directly for a suspect who has not complied with a summons, when the option of compulsory appearance is available, violates the "necessity" element of the principle of proportionality. Legal practitioners (especially Public Prosecutors and judges), when exercising the powers granted to them by law, are obliged to always consider the fundamental principles arising from the Constitution and international conventions that limit these powers. The obligation to choose the least intrusive measure sufficient to achieve the objective, not the one that seems most effective, is a fundamental requirement of the right to a fair trial.
• The Importance of Conceptual Clarity: The knowledge and internalization by all practitioners of the fundamental differences—such as the fact that "compulsory appearance" is not a rehearsal for detention or arrest, that handcuffs cannot be used, and that it does not involve being held in a cell—will prevent arbitrary practices. Likewise, it should not be forgotten that detention is not an automatic process, that it does not necessarily have to be applied after every arrest, and that it only gains legitimacy if the conditions of "necessity" and "concrete evidence" required by law are met.

Ultimately, the effectiveness of the criminal justice system is measured not only by its ability to punish criminals but also by its capacity to protect the rights of individuals under criminal suspicion. The use of powerful authorities such as compulsory appearance, arrest, and detention, filtered through the principles of proportionality, necessity, and balance, as exceptions and only in mandatory cases, is the fundamental condition for preserving the dignity of the state of law and the individual's trust in the justice system.