Reasons and proportionality in pre-trial detention decisions

What matters in a detention decision: how the conclusion was reached

Pre-trial detention restricts a person’s liberty before there is a final conviction. An order simply directing detention is therefore not enough. It must explain which evidence strengthens the suspicion, which concrete risk makes custody necessary and why a less restrictive measure would not suffice.

This article examines the reasons a detention decision should contain, the distinction between initial detention and continued custody, and the role of judicial supervision. It does not give a legal opinion on any particular person or case.

1. Detention is not punishment in advance

Pre-trial detention is not an early finding of guilt. It is a temporary protective measure intended to secure the proper conduct of criminal proceedings. The distinction is fundamental to the presumption of innocence and the right to liberty and security.

Article 19 of the Turkish Constitution protects liberty and security. Under Article 100/1 of the Turkish Code of Criminal Procedure (Law No. 5271; CMK), detention requires concrete evidence showing strong suspicion of an offence and a ground for detention. Detention cannot be ordered where it would be disproportionate to the importance of the matter or the anticipated penalty or security measure.

Under CMK Article 100/2, a ground for detention may be presumed in the following circumstances:

a) The suspect or defendant has fled or gone into hiding, or concrete facts give rise to a suspicion that they will flee.

b) The suspect’s or defendant’s conduct gives rise to a strong suspicion of:

1. Destroying, concealing or altering evidence;

2. Attempting to exert pressure on witnesses, the victim or other persons.

These are the forms of conduct addressed by paragraph (b).

Read the paragraph together with the following list of offences: CMK Article 100 on this website · Current official CMK text.

Merely naming the charge or describing its seriousness does not satisfy these conditions. The decision must connect the facts justifying the restriction of liberty to the case, clearly enough for that connection to be reviewed.

2. The reasons must answer four separate questions

CMK Article 101 requires decisions ordering detention, continuing detention or refusing release to explain four matters through concrete facts. They can be separated into four questions:

Which concrete evidence supports strong suspicion of an offence?

Which ground for detention exists in this case?

Why is detention necessary and proportionate?

Why would judicial supervision be insufficient?

An answer to one question cannot replace an answer to another. A serious charge alone explains neither the concrete evidence nor the risk of flight, nor why judicial supervision would be inadequate.

2.1. Which concrete evidence supports strong suspicion?

The decision must first identify the evidence supporting strong suspicion that the suspect or defendant committed the alleged act. The name or seriousness of the charge, or the size of the case file, cannot answer that question. The connection between the evidence, the person and the allegation must be apparent.

The standard of proof required for conviction is not demanded at this stage. Even so, detention cannot rest on abstract possibilities or a repetition of the charge. The decision must identify the concrete evidence that makes the suspicion strong.

2.2. Which ground for detention exists in the individual case?

Strong suspicion alone is insufficient. Facts pointing to flight or concealment, attempts to destroy, conceal or alter evidence, and conduct suggesting pressure on witnesses, the victim or others require separate assessment.

General statements such as ‘there is a risk of flight’ or ‘the evidence has not yet been collected’ cannot be meaningfully reviewed without an explanation of the underlying facts. The reasons must connect the statutory concept to the actual circumstances.

2.3. Why is detention necessary and proportionate?

Proportionality cannot be inferred solely from the seriousness of the charge. The court must assess whether the measure serves a legitimate procedural purpose, whether a less restrictive measure could achieve that purpose, and the balance between the restriction of liberty and the interest being protected.

CMK Article 100 prohibits detention that would be disproportionate to the importance of the matter and the anticipated sanction. Adding ‘detention is proportionate’ at the end of a decision is not enough: the need for custody must be explained.

2.4. Why would judicial supervision be insufficient?

CMK Article 109 permits judicial supervision (adli kontrol) instead of detention where grounds for detention exist. This Turkish measure involves specified obligations rather than custody. Article 101 requires both the detention request and the decision to identify the legal and factual reasons why it would be insufficient.

A bare conclusion that judicial supervision would fail is inadequate. The court should explain why a particular obligation could not address a particular risk. Moving directly to detention without considering alternatives may leave the necessity assessment incomplete.

3. What is a ‘listed offence’?

In Turkish criminal procedure, ‘catalogue offence’ refers to an offence expressly listed by statute for a particular measure. The list discussed here is the detention list in CMK Article 100/3. It need not be identical to a list governing another protective measure.

Article 100/3 allows a ground for detention to be presumed where concrete evidence supports strong suspicion that a listed offence was committed. The list below retains the offence categories and statutory limitations.

3.1. Offences under the Turkish Penal Code

1. Genocide and crimes against humanity (Articles 76, 77 and 78).

2. Migrant smuggling and trafficking in human beings (Articles 79 and 80).

3. Intentional homicide (Articles 81, 82 and 83).

4. Intentional bodily injury (Article 86, paragraph 3, subparagraphs b, e and f) and intentional injury aggravated by its consequences (Article 87).

5. Torture (Articles 94 and 95).

6. Sexual assault (Article 102, excluding its first paragraph).

7. Sexual abuse of children (Article 103).

8. Theft (Articles 141 and 142) and robbery (Articles 148 and 149).

9. Manufacture of and trafficking in narcotic or stimulant substances (Article 188).

10. Establishing an organisation to commit offences (Article 220, excluding paragraphs 2, 7 and 8).

11. Offences against state security (Articles 302, 303, 304, 307 and 308).

12. Offences against the constitutional order and its functioning (Articles 309, 310, 311, 312, 313, 314 and 315).

3.2. Other subparagraphs of CMK Article 100/3

b) Arms-smuggling offences defined in Article 12 of the Law on Firearms, Knives and Other Instruments (Law No. 6136).

c) Embezzlement defined in Article 22, paragraphs 3 and 4, of the Banking Law (Law No. 4389), as referenced in the CMK text.

d) Offences punishable by imprisonment under the Anti-Smuggling Law (Law No. 4926), as referenced in the CMK text.

e) Offences defined in Articles 68 and 74 of the Law on the Protection of Cultural and Natural Assets (Law No. 2863).

f) Intentional forest-burning offences defined in Article 110, paragraphs 4 and 5, of the Forest Law (Law No. 6831).

g) Offences listed in Article 33 of the Law on Meetings and Demonstration Marches (Law No. 2911).

h) Offences specified in Article 7, paragraph 3, of the Anti-Terror Law (Law No. 3713).

i) Intentional bodily injury committed against a woman.

j) Intentional bodily injury against personnel serving in healthcare institutions, during or because of their duties.

k) Intentional bodily injury, during or because of their duties, against administrators, teachers and master instructors in official educational institutions affiliated to the Ministry of National Education; instructors, teachers and guidance counsellors in Ministry projects for foreign students; administrators, teachers, specialist instructors and master instructors in private educational institutions; persons teaching for hourly remuneration in those official or private institutions; and teachers serving in other public institutions.

The list follows the official consolidated text of CMK Article 100/3 accessed on 8 September 2026. Its paragraph and subparagraph limitations matter; a similar offence name is not enough. In particular, subparagraphs (c) and (d) retain the law numbers still used in the CMK. These references do not mean every provision of those laws remains in force. Relevant replacement legislation, reference rules and transitional provisions must also be considered in an individual case. Current official text.

3.3. Why does inclusion in the list not make detention automatic?

CMK Article 100 permits a ground for detention to be presumed for listed offences where strong suspicion rests on concrete evidence. It does not require the court to order detention.

The evidential basis for strong suspicion, proportionality and the inadequacy of judicial supervision still require separate examination. Inclusion in the list is not an automatic formula dispensing with an assessment of the person and the case.

The individual-application judgments discussed below concern reasons and reasonable duration in continued detention, not the annulment of the statutory list.

4. Listing statutory provisions is not sufficient reasoning

A string of statutory references does not itself make a decision reasoned. Reasons make the connection between the legal rule and the facts visible. The reader should not be left asking:

Which evidence supports strong suspicion?

Which concrete facts create the risk of flight, interference with evidence or pressure?

Does that risk still exist on the date of the decision?

Why is a less restrictive measure considered insufficient?

Why is detention proportionate at the present stage of the case?

Clarity matters beyond the suspect or defendant. Defence counsel needs intelligible reasons to prepare an effective objection, and the reviewing authority needs them to scrutinise the decision. Article 101’s requirement that the content be communicated orally and a written copy supplied also serves that scrutiny.

5. Initial reasons cannot simply be carried into continued detention

Lawfulness is not assessed only when detention is first ordered. Under CMK Article 108, detention during the investigation must be reviewed at intervals of no more than thirty days. During trial, the court decides on continued detention at every hearing and, where circumstances require, between hearings.

The case changes over time: evidence is collected, risks diminish or disappear, and proceedings move to another stage. Repeating the initial reasons is therefore insufficient. Continued detention requires current, individualised facts explaining why custody remains necessary that day.

Both the Turkish Constitutional Court and the European Court of Human Rights’ Article 5 case-law reject general, abstract reasons and automatic repetition. Each review must address whether detention remains necessary and proportionate at that time.

6. What can be examined when challenging detention?

An objection depends on the evidence and procedural position of the case. Reviewing the reasons may nonetheless usefully separate these questions:

Evidence: What is said to support strong suspicion, and how is it connected to the person?

Risk: Which concrete facts support flight, concealment, interference with evidence or pressure?

Current circumstances: Do the stated risks persist on the decision date?

Judicial supervision: Is the inadequacy of available obligations explained?

Proportionality: Are the stage of proceedings, anticipated sanction and severity of the restriction considered together?

Reviewability: Are the reasons sufficiently clear for defence counsel and the reviewing authority?

These questions are not an application or petition template. The time limit, competent authority, evidential arguments and relief sought must be determined separately for each case.

7. Two Constitutional Court judgments on liberty and security

7.1. Hanefi Avcı: individualised reasons for continued detention

In Hanefi Avcı, the Constitutional Court examined approximately two years and ten months of detention and the reasons for refusing release (Application No. 2013/2814, 18 June 2014). After a certain period, the general state of the case alone cannot suffice: the applicant’s particular circumstances must also be assessed. Extending facts about other defendants to everyone in the same case can undermine individualisation (§§ 74, 83–85).

The continuation orders repeated the same considerations without relevant and sufficient reasons for further detention. The Court found a violation of Article 19, paragraph 7, of the Constitution (§ 86). It did not, however, uphold the allegation that the initial detention lacked strong suspicion and a detention ground (§§ 52–53). The violation concerned prolonged custody and formulaic refusals of release. Lawful initial detention does not automatically make every subsequent continuation order lawful.

Full judgment: Hanefi Avcı — Constitutional Court judgments database.

7.2. Mehmet Güneş: repeating reasons does not justify the duration

In Mehmet Güneş, the Court assessed detention lasting three years, four months and twenty-nine days (Application No. 2014/1268, 17 May 2016). Across twenty-four hearings, decisions referred to the nature of the offence without concrete facts. Some also repeated uncollected evidence, flight risk or the anticipated sentence. One hearing supplied no reasons for continuing detention (§§ 53, 60).

The reasons were repeated without individualisation or a concrete connection to strong suspicion and detention grounds. They were not relevant and sufficient for the duration of this applicant’s detention, leading to a violation of Article 19, paragraph 7 (§§ 61–62). This is not a rule requiring automatic release in every case after a fixed period. It identifies the failure to provide current, individualised justification throughout the deprivation of liberty.

Full judgment: Mehmet Güneş — Constitutional Court judgments database.

8. Conclusion

For a measure as serious as deprivation of liberty, reasons are central to reviewing lawfulness, not a formality. Concrete evidence supporting strong suspicion, the risk necessitating detention, the inadequacy of judicial supervision and proportionality must each be explained.

Nor is this a one-off explanation. As detention continues, the reasons must reflect the changing case. That makes the deciding authority’s assessment visible and enables meaningful scrutiny by defence counsel and the reviewing authority.

References

Constitution of the Republic of Türkiye, Articles 13 and 19.

Turkish Code of Criminal Procedure (Law No. 5271), Articles 100, 101, 108 and 109 — current official consolidated Turkish text.

Legislation on this website: CMK Article 100 — grounds for detention.

Constitutional Court, Hanefi Avcı, Application No. 2013/2814, 18/6/2014, particularly §§ 52–53, 74, 83–86 — official judgment.

Constitutional Court, Mehmet Güneş, Application No. 2014/1268, 17/5/2016, particularly §§ 53, 59–62 — official judgment.

Constitutional Court: leading judgments on liberty and security.

ECtHR Guide on Article 5 of the European Convention on Human Rights, updated 28 February 2026.

Scope of this information

This is a general examination of reasons and proportionality in detention decisions. Evidence, procedural stage and personal circumstances differ in every case. It is not a substitute for individual legal advice or an opinion on a particular file.