Traffic records from telephones can make a significant contribution to examining communication between persons and the sequence of events in a criminal file. However, a call record does not by itself show that the conversation was criminal, and a service received from the same base station does not by itself show that two people met face to face. There must be an explainable link between the fact the technical data shows and the conclusion the court draws from it. See also: Digital evidence in criminal proceedings: phone examination and objections.
Short answer: Depending on the category of records obtained, HTS records can provide information on the parties to a communication, the time, the duration and the type of record, as well as base station information. They do not show the content of the conversation. A base station record alone does not determine a device's exact address or the identity of the person using it. Even so, these records are not entirely without value. Lawful acquisition, correct technical analysis, personalization and examination of the defense's concrete objections are the basic conditions of their evidentiary value. [1][2][3]
The difference between HTS records, interception and base station data
Traffic data and communication content
In the printouts referred to as HTS, depending on the nature of the records obtained, the calling and called numbers, date, time, duration, transaction type and related technical identifiers may appear. However, the fact that one number called another does not show what the parties said. Traffic information about messaging is also not the same as the text of the message. The report must clearly state which type of data was examined.
This distinction becomes an important defense question in practice: does the allegation rest on the fact that communication took place, on its content, or on presence at a particular place? If the record answers only the first question, the additional evidence on which the other conclusions are built must be explained. Reading the same table and moving through a chain of assumptions to conclusions about contact, meeting, agreement and criminal intent is not sufficient.
The legal basis depends on the measure used
CMK 135/1 regulates the interception of communications, their recording and the evaluation of signal data; CMK 135/6 regulates the determination of communications (iletişimin tespiti). Without determining the status of the person concerned, the stage of investigation or prosecution, the type of record and the scope of the order, no single article number can explain all the operations. Likewise, the catalogue of offenses relating to interception and signal evaluation must not be applied without separating its scope from the determination of communications.
The defense should review together the request, the decision of the judge or court, any prosecutor's decision and approval steps, the letter sent to the operator and the data received. A difference between the time range set out in the decision and the range actually obtained is a point requiring examination. In broad data sets concerning third persons beyond the charge, the relationship between purpose and scope also matters.
Does a base station record show the exact location?
The cell a device uses and the point where it is
Base station and sector information provides data on the network element a device used during a specific communication event. This is not, by itself, a determination of a street number or a specific room. A point marked on a map without considering coverage, antenna direction and network conditions should not be read as the device's exact location. The SWGDE guidance on historical cell site analysis also emphasizes that records do not by themselves show an exact address or the actual user. [2]
For the file, the result is this: the proposition "it was served by this base station" and the proposition "they were in the building where the crime took place" are assessed separately. To establish the second, the position of the crime scene within coverage, the time window and other evidence must be examined. Marking a base station pole on a map does not show that the person was at the location of the pole.
Coverage areas are not fixed circles
Antenna direction, sector structure, geographic and structural conditions, and network characteristics matter in the coverage assessment. The edge of a sector drawn for visualization also cannot always be treated as a precise physical boundary in every event. A measurement taken long after the event does not automatically reconstruct the past state of the network. These technical limitations must be explained in the report. [2][3]
The defense should not be satisfied with the general statement that "base stations cover a wide area." Specific questions must be asked: what the information for the relevant base station was on the date of the event, which sector was used, which data the map in the report relies on, and whether alternative locations can be excluded. When the limits of the examination are correctly determined, the data may sometimes support the allegation and sometimes strengthen the defense's claim of being elsewhere.
Does being on the same base station prove a meeting?
The gap between shared coverage and shared action
Two devices receiving service from the same or nearby base stations may show a technical relationship to the same area. However, that area may contain a workplace, a hospital, a transport route, a school or many homes. The fact that persons appear within the same coverage at the same time, and the fact that they gather together or agree on a crime, are separate matters. The transition between them must be explained with evidence specific to the file.
Hypothetically, two persons working in the same hospital who receive service from the same base station during working hours may have an ordinary explanation. On the other hand, when a time sequence closely overlapping with the event is combined with other communications, camera footage and records showing joint movement after the act, a different assessment may be made. What is decisive is a serious examination of alternative explanations.
Many weak indicators do not always amount to strong proof
Different tables derived from the same source should not be presented as independent evidence. For example, a call list, a contact diagram and a map produced from the same HTS printout are not three separate verification sources. An increase in the number of visuals does not reduce uncertainty in the database. It must be shown on which original records the analysis is built.
This assessment does not mean that all indirect evidence is insufficient. Facts that independently corroborate one another may be important. The defense's task is to focus not on the number of tables, but on their sources, their relationship to one another and their power to explain the elements of the offense.
How to separate line subscriber, device and actual user
A subscription record is the starting point of attribution
That a line is registered in the defendant's name does not, by itself, prove that it was used by them on the date of the event. Family use, a workplace phone, loss or theft of a device, temporary use and claims that a line was obtained in another person's name must be examined with concrete evidence. On the other hand, merely saying "I was not using the line" may be insufficient without explaining the pattern of regular use and the other records.
The application should state in which period the line was with whom, how the relationship with the device was established, and which records could confirm this account. If the device identifier changed, or if there are claims of multiple SIM cards or shared use, an assessment requiring technical expertise should be requested. The date on which the phone was physically seized does not automatically determine the user for every past transaction.
Confirming attribution does not confirm content
Even if the line is accepted as having been actually used, the purpose of the call is still examined separately. If communication established for business, health, family, commercial or public service reasons is possibly connected to the event, it must be investigated. The defense's alternative explanation should not be left abstract; it should be tied to verifiable grounds such as a work record, an appointment, a duty document or the statement of the person concerned.
This distinction is particularly important in claims of organizational contact and joint action. The existence of a connection and the criminal nature of that connection are not the same finding. The court's reasoning must not only count the contacts but also explain what they mean for the relevant offense.
Zero-second, duplicate and counterpart record issues
No conclusion should be drawn without explaining the transaction type
The technical event represented by a zero-second line must be determined from the explanation of the relevant record system. Just as not every record can be accepted as a successful conversation, the presence of a zero-second entry does not in every case mean that no communication attempt was made. Calls, call forwarding, data sessions and other record types must be distinguished from one another.
Duplicate appearances are examined in the same way. A communication producing several lines in different systems of the network is not the same as several calls actually being made. In the Murat Albayrak decision, the Constitutional Court (Anayasa Mahkemesi, AYM) dealt with such numerical objections by comparing reciprocal records and considering the event as a whole. [4]
Why counterpart line records are requested
Comparing the data of one party with the relevant records of the other party helps to investigate discrepancies. However, it must also be checked whether the two data sets are of the same type, on the same time standard and within the same scope. The fact that tables obtained with different filters do not overlap one-to-one does not by itself produce a false record result.
An effective objection shows the discrepant line with its date and time, explains which assumption of the report it affects, and requests the additional record needed. Instead of stating that "the HTS records are contradictory," it explains why a specific call cannot serve as a basis for the conclusion in the report. This method clarifies the question the court must answer.
Sequential and periodic call analyses
Technical pattern and organizational characterization
Detecting calls made consecutively or at regular intervals is first a matter of technical analysis. Whether this pattern counts as organizational communication requires legal assessment together with the person's role, the line used, the other persons called, the period, witness statements and the other findings in the file. Not every consecutive call can be counted as an indicator of crime; nor can a pattern analyzed in detail in a specific file be dismissed as unimportant from the start.
Particularly for call records from publicly accessible fixed telephones or payphones, identifying the persons called, their places of work, ordinary communication explanations and counterpart records is important. Repeating the same report sentence for all persons does not show that each person's situation was actually examined. Personalized analysis and responses to objections must be sought.
The scope of the inquiry must be proportionate and relevant
Defense requests need not be framed as placing all telephone records of unlimited duration on the file. The period and the lines concerned, and the reason they are necessary, should be explained. When records affecting the scope of the allegation are requested, the unrelated communication data of third persons is also taken into account. Access to necessary and decisive data is different from the accumulation of unnecessary data.
Real Constitutional Court decisions: violation and inadmissibility
Üzeyir Yıldızoğlu: technical objections left unanswered
In the decision Üzeyir Yıldızoğlu, Application No. 2022/100969, July 2, 2025, the applicant raised the inconsistency between call records, claimed that some calls had not taken place, argued that the fixed-line and counterpart base station information had not been sufficiently examined, and put forward a professional communication explanation. The Constitutional Court found a violation of the right to a reasoned decision because defenses capable of changing the outcome were not openly evaluated; §§ 27–31 are decisive. [5]
The decision does not mean that HTS records are invalid or inadmissible evidence in all cases. The focus of the violation is the failure to evaluate concrete technical and factual objections. For a similar application, it is therefore not enough to cite the decision's name; it must be shown which objection was raised, on what date, and why it remained unanswered in the judgment.
Murat Albayrak: not every HTS objection leads to a violation
In the decision Murat Albayrak, Application No. 2020/16168, March 8, 2023, the Constitutional Court found no violation of the right to a fair trial with respect to complaints about the method of obtaining communication determination data. It regarded the claim that the records could not be used as sole or decisive evidence as manifestly ill-founded and therefore inadmissible. These two outcomes must be kept distinct. [4]
The Court took into account the evaluation carried out together with reciprocal records and other findings, the defense's opportunity to object and the concrete inquiries made. The explanations in §§ 130–147 of the decision show that technical data was not categorically accepted or rejected. The finding of adequate inquiry in that file does not automatically remedy an incomplete examination in another file.
Mustafa Seyhan: the link between contact and the offense must be explained separately
In the decision Mustafa Seyhan, Application No. 2021/58283, October 1, 2025, the Constitutional Court examined the reasoning of the conviction for membership of an organization. The HTS contact, workplace and money transfer claims were discussed in the file, but the failure to explain their organizational nature was debated there; the Court ultimately found a violation of the right to a reasoned decision. However, § 46 of the decision also notes that these claims were not made the basis of the conviction by the first-instance court.
For this reason, it is not accurate to summarize the decision as "a conviction was quashed simply because a signal was received from the same base station." Its practical contribution is to show that the concept of contact cannot replace the elements of the offense, and that the basis of a conviction must be read carefully to determine which evidence it actually relies on.
Preparing an effective objection to an expert report
Comparing raw records with the analysis table
The primary call printouts underlying the report, the operator's explanations and any filtering criteria should not be left unexamined in favour of the result table alone. The date range, time standard, transaction types, treatment of duplicate records and person matching are all checked. The possibility that rows belonging to someone other than the applicant were mixed in, or that the selected time window excluded the defense, is investigated against the raw records.
| Issue | Requested explanation or record | Targeted legal assessment |
|---|---|---|
| Same-base-station assumption | Base station and sector information for the time of the event | Limit of the claim of exact location |
| User attribution | Matching of line, device and period | Attribution of the act to the person |
| Contradictory duration | Transaction type and counterpart record | Nature and number of the calls |
| Sequential calls | Other persons called, period and comparison | Personalization of the pattern |
| Missing data | Raw printout and filter used | Verifiability of the result |
| Lack of context | Duty, work, travel or camera record | Examination of non-criminal explanations |
Making a request for further examination specific
A request for a new expert or supplementary report may have limited effect if it rests only on disagreement with the earlier report. It should state which calculation, matching or assumption is wrong. Questions supported by expert opinion make the court's evaluation easier. A technical expert must not substitute for the court and issue a finding of guilt.
This topic can be considered together with objection to an expert report, scrutiny of witness statements and cross-examination and acquittal for insufficient evidence. Objecting only to the terminology of the report, without establishing the link between a technical error and the insufficiency of proof, is not enough.
Use at the pretrial detention and appeal stages
The threshold of suspicion and the standard for conviction
The fact that HTS data creates a line of inquiry in the investigation does not mean that the same data is by itself sufficient for a final conviction. At the pretrial detention stage, strong suspicion based on concrete evidence is at issue; at the judgment stage, proof of the offense is debated. The defense must frame its request according to the standard that applies at the stage the file has reached.
Carrying the objection into the appeal process
In an appeal (istinaf) and an appeal on points of law to the Court of Cassation (temyiz), it must be shown not only which finding in the report is wrong but also how that error affected the judgment. Where it is claimed that a substantive objection was not evaluated by the first-instance court, the relevant petition and the date of the minutes are indicated. If an application to the Constitutional Court is being considered, whether the complaint was raised through the ordinary remedies, together with the time limits and admissibility conditions, is also examined separately. Individual application to the Constitutional Court in criminal cases sets out the framework of this final stage.
For related details, see also digital evidence and WhatsApp messages in criminal cases and hearing of witnesses and experts.
Conclusion
The legal value of HTS and base station records depends on interpreting technical data within the correct limits. The record, the device, the user, the location and the link to the offense are separate questions. A strong defense sets out its decisive objections by examining the raw data, the method used and the alternative explanations. Real judicial decisions likewise emphasize case-specific research and scrutiny of reasoning, rather than an approach that either rejects all records in advance or accepts them without question.
For legal support in criminal proceedings and enforcement, see our criminal law services.
Frequently Asked Questions
Do HTS records contain the content of a conversation?
A traffic record is neither the text nor the audio of a conversation. It may provide information on which numbers were involved, when, and in what type of transaction. Obtaining content is a separate measure and subject to its own assessment.
Are persons who receive a signal from the same base station necessarily together?
No. They may be in different places within a common coverage area. A claim of a meeting must be examined separately with the time, the sector, the place of the event and other evidence.
If the line is in my name, am I responsible for all transactions?
The subscription is an important starting point; however, actual use and the connection with the offense are examined separately. If you claim that you did not use the line, you should show the period of that claim and its verifiable grounds.
Does a zero-second record necessarily show that no call was made?
No definite conclusion can be drawn without examining the record type and the operator's technical explanation. Successful calls, call attempts and other transaction records must be distinguished.
If there is an HTS report, is an objection to the expert pointless?
No. The scope of the data, the matching, the time, the duplication and the analysis method can all be examined. An objection based on concrete lines and results is more effective than a general critique of the report.
Does a Constitutional Court violation decision on HTS end all similar cases?
No. The ground of violation and the similarity to the concrete file are assessed. A violation of the right to a reasoned decision does not by itself mean an acquittal; it requires a reassessment suited to remedying the violation.
Sources and legal bases
- Law No. 5271, Code of Criminal Procedure (Ceza Muhakemesi Kanunu), especially Articles 63, 67, 100, 135, 206, 217 and 230. Current text checked: October 12, 2026.
- SWGDE, Best Practices for Historical Cell Site Analysis, 17-F-001-5.0. Version dated July 9, 2026 in the current document list; technical reference source.
- Forensic Science Regulator, Statutory Code of Practice, Version 2, technical sections on historical cell site analysis and location assessment. Not used as a binding procedural rule in Turkish law.
- Constitutional Court, Murat Albayrak, Application No. 2020/16168, March 8, 2023, especially §§ 130–147 and the operative part.
- Constitutional Court, Üzeyir Yıldızoğlu, Application No. 2022/100969, July 2, 2025, especially §§ 27–34.
- Constitutional Court, Mustafa Seyhan, Application No. 2021/58283, October 1, 2025, especially §§ 43–54 and 59.