Can phone messages and WhatsApp conversations be used as evidence in drug-related crimes?

In investigations into drug-related crimes, mobile phones are currently one of the most important sources of evidence. In particular, messages exchanged on messaging applications like WhatsApp and Telegram, SMS records, call histories, contact lists, photos, location information, and other digital data are frequently examined by investigative authorities.

In drug trafficking cases, law enforcement and public prosecutors use telephone conversations and text messages to establish contact between suspects. However, the mere presence of messages suspected of being related to drugs on a person's phone does not automatically mean that person can be convicted of drug trafficking.

In criminal procedure, the fundamental issue is not merely the existence of evidence; it is the lawful acquisition of the evidence, the verification of its authenticity, the determination of its attribution to the accused, and its ability to prove the alleged crime beyond any reasonable doubt.

Therefore, when evaluating WhatsApp and phone messages in drug-related crimes, the following questions should be examined separately:

On what legal basis was the phone examined? Was it determined that the messages actually belonged to the defendant? Was the entire correspondence included in the file, or only certain parts? Was it confirmed by concrete evidence that the statements in the messages relate to narcotics? Were narcotics seized from the defendant or related individuals? Were the messages supported by physical surveillance, camera footage, money transfers, witness testimonies, or other material evidence?

The answers to these questions are of vital importance, especially with regard to the crime of trafficking in narcotics or stimulants, as defined in Article 188 of the Turkish Penal Code

1. Can WhatsApp messages be used as evidence in a criminal case?

Turkish criminal procedural law does not have a limited system of evidence stating that "only certain types of evidence can be used as proof." According to the fundamental approach of Article 217 of the Code of Criminal Procedure, the alleged crime by any evidence obtained lawfully . Conversely, evidence obtained unlawfully cannot be used as the basis for a judgment. Article 38 of the Constitution also explicitly guarantees that findings obtained unlawfully cannot be accepted as evidence. The Constitutional Court also emphasizes that this prohibition is one of the fundamental safeguards of criminal procedure.

Therefore, WhatsApp messages, SMS messages, Telegram messages, emails, or any other digital communication record can, in principle, be considered evidence in criminal proceedings.

However, two different concepts must be distinguished here:

The fact that a message can be used as evidence is not the same as a person being convicted solely on the basis of that message.

Especially in crimes with severe penalties, such as drug trafficking, the court must consider material facts and other evidence in addition to the messages.

2. Is a court order required to examine the phone?

One of the most important legal debates in drug investigations is the method by which WhatsApp and other digital data on phones are examined.

Article 134 of the Code of Criminal Procedure regulates a specific protective measure regarding searching, copying, and seizing computers, computer programs, and computer files. In practice, the examination of digital data contained in mobile phones is also considered within the scope of this provision.

In a significant decision by the 10th Criminal Chamber of the Supreme Court of Appeals, it was explicitly accepted that a legal decision under Article 134 of the Code of Criminal Procedure is required to examine a suspect's mobile phone and record the messages on the phone.

The 10th Criminal Chamber of the Court of Cassation, in its decision numbered 2023/15758 E., 2024/18787 K., reviewed a conviction for drug trafficking. In this specific case, WhatsApp messages on the defendant's phone were recorded in a "preliminary phone examination and seizure report." However, there was no decision or written order in accordance with Article 134 of the Code of Criminal Procedure.

The Supreme Court the defendant's consent to the phone examination alone is not sufficient, and that WhatsApp messages obtained without following the procedure prescribed by law do not constitute legally admissible evidence and cannot be used as the basis for a judgment.

This decision is particularly important for drug investigations, as in practice, it is sometimes the case that a person's phone is turned on during an arrest, messages are seen by law enforcement, and these are then recorded in the file as screenshots or in a written report.

However, seizing digital material and investigating data contained within a phone for forensic purposes are two different processes.

The fact that the phone is found on the suspect does not give law enforcement the unlimited authority to examine all private communications contained within the phone.

3. Important Constitutional Court Decision Regarding Article 134 of the Code of Criminal Procedure as of 2026

A very important development occurred in terms of digital evidence in 2026.

The Constitutional Court, in its decision dated February 12, 2026, numbered E.2023/128, K.2026/36, annulled Article 134 of the Code of Criminal Procedure concerning digital searches and seizures on the grounds that it did not contain sufficient safeguards for the protection of personal data. The decision was published in the Official Gazette on May 25, 2026. However, since the entry into force of the annulment was postponed for nine months, it will come into effect on February 25, 2027.

Therefore, as of July 2026, Article 134 of the Code of Criminal Procedure will continue to be applied in its current form.

The Constitutional Court's decision specifically highlighted the inadequacy of legal regulations regarding the storage, deletion, and restriction of the use of personal data obtained from digital materials, as well as the safeguards provided to the data subjects.

This development will lead to a reshaping of criminal procedure practices regarding telephone and computer examinations in the coming period.

4. Is consenting to the examination of the phone sufficient?

One of the most frequently asked questions in practice is this:

"If the suspect voluntarily unlocked the phone, would the WhatsApp messages be considered evidence?"

The aforementioned decision of the 10th Criminal Chamber of the Court of Cassation dated May 15, 2024, is quite clear on this matter.

The ruling stated that a telephone examination conducted without a court order or written directive, as required by Article 134 of the Code of Criminal Procedure, would not constitute legally admissible evidence, even if the suspect consented.

Therefore, the existence of situations such as "I turned on my phone myself," "I gave my password myself," or "I said the police could check" does not eliminate the procedural safeguards required by the Code of Criminal Procedure in every case.

From a defense standpoint, therefore, the first thing to consider in the file is:

phone review decision,

prosecutor's order,

judicial approval,

seizure report,

phone inspection report,

digital forensics report,

records of delivery and storage of digital material

It should be examined.

5. Can WhatsApp messages alone prove the crime of drug trafficking?

This is the most important question.

In drug trafficking cases, telephone conversations and WhatsApp messages can constitute important evidence. However, the established approach of the Supreme Court of Appeals is cautious about establishing convictions solely on the basis of telephone conversations or message content, especially if no drugs have been found on the defendant and the meaning of the messages is unclear.

In its decision numbered 2020/16294 E., 2022/9320 K., the 10th Criminal Chamber of the Court of Cassation overturned the convictions on the grounds that no narcotics or stimulants were found in the possession of the defendants and that, apart from telephone conversations whose content could not be fully determined, there was no conclusive evidence linking them to the substances in question.

Similarly, in the decision numbered 2018/2496 E., 2023/5209 K. of the 10th Criminal Chamber of the Court of Cassation, it was accepted that telephone conversations, the content of which could not be fully determined, were not sufficient for conviction in the case of a defendant who was not found to have drugs on his person, in his home, or at his workplace.

The Supreme Court's 20th Criminal Chamber, in its decision numbered 2018/1288 E., 2019/6405 K., stated that since no narcotics were found on the defendant, the telephone conversations were not supported by concrete facts and material evidence, and other statements remained abstract, there was insufficient and conclusive evidence for conviction on charges of drug trafficking.

When these decisions are considered together, the fundamental principle that emerges is this:

Telephone conversations and message contents are important evidence; however, especially when their content is open to interpretation, they may not be sufficient for conviction for drug trafficking without supporting material and objective evidence.

6. Is it sufficient for messages to contain words like "goods," "package," "sugar," "green," and "white"?

It could be argued that in drug investigations, suspects do not directly use terms like "drugs," "cocaine," "marijuana," or similar words; instead, they employ various code words.

For example, in messages;

"The goods are ready"

"Bring two packages,"

"We need five"

"Do you have any green ones?"

"White arrived",

"leave the trust behind"

"send the money"

It is possible to find expressions such as these.

However, in criminal proceedings, convictions cannot be established by assigning hypothetical meanings to words.

The prosecution must demonstrate, with other evidence from the specific case, that the word "mal" in the message refers to narcotics.

For example, if physical surveillance conducted immediately after the message leads to a meeting between the parties, and if drugs are found on the person alleged to be the recipient after the meeting, and the amount of drugs matches the amount stated in the message, or if a money transfer is detected, the evidentiary value of the message can be significantly strengthened.

Conversely, if no drugs are seized, no delivery is observed, no money transfer is found, and the message content is open to multiple interpretations, serious doubts may arise regarding the justification for punishment.

Indeed, in various decisions of the Supreme Court of Appeals, it has been emphasized that telephone conversations that "do not correspond to concrete events and facts" or "are not supported by material evidence" cannot be considered conclusive evidence. The decision of the 9th Criminal Chamber of the Supreme Court of Appeals, numbered 2015/665 E., 2015/6293 K., is one example of this approach.

7. Is it important that the drugs discussed in the messages are not seized?

Yes.

In drug trafficking offenses, the subject of the crime is drugs or stimulants. If it is alleged that the trade of a specific substance was discussed in a phone call or WhatsApp message, it is crucial to support the claim that the conversation relates to an actual drug transaction with material evidence.

In its decision numbered 2013/13687 E., 2014/1432 K., the 10th Criminal Chamber of the Court of Cassation noted that because the substances mentioned in the telephone conversations could not be seized, they could not be considered narcotics or stimulants, and that telephone conversations not supported by material evidence were not sufficient for conviction.

This approach is particularly important in cases where alleged past sales are inferred solely from message content.

For example, the presence of phrases like "send 10" or "money is ready" in a phone conversation six months ago does not automatically prove drug trafficking in the absence of any other material evidence.

8. What kind of evidence strengthens WhatsApp messages?

In drug trafficking cases, the probative value of digital correspondence depends on its consideration alongside other physical evidence.

For example, messages;

seizure of narcotic substances,

criminal laboratory report,

physical surveillance records,

camera footage,

HTS and base station records,

money transfers,

bank account transactions,

meetings between suspects,

the way the drug is packaged,

precision scales or packaging materials,

witness or recipient testimonies,

other physical evidence obtained as a result of the search

Matching the information can increase the evidentiary value of the messages.

Here, no single piece of evidence should be evaluated mechanically in isolation. The court must consider all the evidence together to determine whether the event actually occurred and in what capacity the defendant participated in it.

9. Can WhatsApp messages in the form of screenshots be used as evidence?

Another problem is messages that are only submitted as screenshots.

Screenshots can also be considered as evidence. However, because screenshots can be easily altered digitally, debates about their authenticity and integrity may arise.

For example, the defendant;

"This correspondence is not mine,"

"The number belongs to me, but I didn't send the message."

"Parts of the messages have been cut out,"

"The parts of the conversation before and after were not included in the file."

"The screenshot has been altered."

They can defend themselves in this way.

In such a situation, instead of relying solely on a printed screenshot, it is crucial to conduct a digital forensic examination of the device containing the message, if possible, to assess the date, time, and integrity of the conversation.

In criminal proceedings, the evaluation of digital evidence requires not only what the content says, but also the reliable establishment of who actually created that content and whether it was included in the file without alteration

10. Can WhatsApp messages secretly obtained from someone else's phone be used as evidence?

From a legal standpoint, how the message was obtained is also extremely important.

Submitting a WhatsApp conversation that one is a party to to the authorities is not the same legal situation as secretly accessing a third party's phone and obtaining their conversations.

While the principle of a person who is the direct recipient of a message presenting that message to the prosecutor's office or court is evaluated differently, cracking someone else's phone password, secretly tampering with the phone, or illegally obtaining conversations to which one is not a party can pose problems in terms of the confidentiality of communication and the protection of private life. The Supreme Court's Criminal General Assembly also evaluates the distinction between the lawful and unlawful acquisition and disclosure of communication content.

Therefore, not every WhatsApp screenshot automatically becomes legally admissible evidence simply because its content relates to a crime.

11. Can Deleted WhatsApp Messages Be Used as Evidence?

During a digital forensics examination of a phone, it may be technically possible to detect some deleted records or digital traces related to them.

However, the same fundamental principles apply in terms of whether such a record can be used as the basis for a judgment:

The data must be obtained through lawful methods, its attribution to the suspect must be established, its integrity must be reliably verified, and the connection between the content and the crime must be explained with concrete evidence.

The assumption that "he is guilty because he deleted it" is incompatible with the standard of proof in criminal procedure.

The fact that the message has been deleted is not, by itself, an indication that drug trafficking took place.

12. Are phone taps and recorded WhatsApp messages the same thing?

No.

This distinction is often confused in practice.

The subsequent examination of WhatsApp messages previously sent and stored on the device constitutes an investigation of digital material.

Conversely, the detection, interception, and recording of the suspect's or defendant's ongoing telecommunication communications are subject to the special protective measures outlined in Article 135 and subsequent articles of the Code of Criminal Procedure.

According to Article 135 of the Code of Criminal Procedure, the conditions of suspicion and subsidiarity specified in the law must be met for communications to be monitored. There is also a catalog of offenses related to listening to and recording communications.

The crime of manufacturing and trafficking in narcotics or stimulants is considered one of the serious offenses defined by law.

However, even the existence of a communication surveillance order does not automatically mean that all conversations constitute evidence of conviction. The specific defendant to whom the recordings relate, the scope and duration of the order, and the connection of the recordings to the alleged crime must be considered separately.

Indeed, in its decision numbered 2019/8619 E., 2022/6623 K., the 10th Criminal Chamber of the Court of Cassation held that telephone conversations obtained without a necessary communication surveillance order are unlawful and cannot be used as the basis for a judgment against the defendant.

13. Can WhatsApp Messages Be Used to Distinguish Between Articles 188 and 191 of the Turkish Penal Code?

One of the most important legal problems in drug cases is the nature of the act;

Drug trafficking under Article 188 of the Turkish Penal Code

mi,

or?

Purchasing, accepting, possessing, or using drugs for personal use, within the scope of Article 191 of the Turkish Penal Code

The goal is to determine whether or not it is.

Article 191 of the Turkish Penal Code stipulates a prison sentence of two to five years for anyone who purchases, accepts, possesses, or uses narcotic or stimulant substances for personal use.

In contrast, Article 188 of the Turkish Penal Code imposes much harsher penalties on individuals who sell, offer for sale, give to another person, dispatch, transport, store, purchase, accept, or possess narcotic or stimulant substances within the country.

Therefore, message content can play an important role in determining the nature of a crime.

For example, messages indicating that the defendant was only trying to obtain drugs for his own use could support an assessment under Article 191 of the Turkish Penal Code.

Conversely, correspondence from a person who regularly quotes prices, specifies quantities, organizes deliveries, and receives payments from numerous individuals can be used, along with other material evidence, to establish commercial intent.

However, one should not automatically conclude that Article 188 of the Turkish Penal Code applies based on a single word or a few messages.

14. How does the principle of "the benefit of the doubt goes to the accused" apply to WhatsApp messages?

In criminal proceedings, conviction must be based on conclusive and convincing proof, not probability.

If a message can be interpreted in two different ways, and there is no objective evidence to show that the message relates to drug trafficking, then "the benefit of the doubt goes to the accused," , comes into play.

For example:

"Bring five."

If a message like this is alleged to be related to drugs, it should be explained why it is considered to be related to drugs.

The situation is different if the drug delivery was detected immediately after the message.

However, if no drugs were seized, the parties to the meeting suggested a different meaning, and no material evidence was found to refute this, then establishing a harsh conviction based solely on speculative interpretation becomes legally questionable.

the Supreme Court, in numerous rulings concerning drug trafficking, emphasizes that telephone conversations correspond to concrete events and facts and be supported by material evidence .

15. What factors should be considered in the defense against phone examination in drug cases?

In a drug case involving phone and WhatsApp messages, it is not sufficient for the defense to simply respond to the content of the messages.

First, the legality of the method used to obtain the evidence must be examined.

On what date was the phone seized? What is the date of the investigation order? Who conducted the initial investigation? Was the phone's contents accessed before the order was issued? Are there any discrepancies between the initial police report and the subsequent forensic IT report?

Secondly, the origin of the message should be investigated.

Even if the phone and line are registered in the defendant's name, who actually used the phone on the relevant date may also be important.

Thirdly, the integrity of the messages should be examined.

The prosecution or law enforcement may have only included five messages that they thought supported the accusation, but not the hundreds of preceding and subsequent messages of the same conversation. In this case, the conversation may have been taken out of context.

Fourth, the relationship between the message and the material evidence should be evaluated.

Where were the drugs allegedly discussed in the message seized? How was the suspect connected to them? Was there physical surveillance? Was there any money transfer? Is there a statement from the person who received the drugs? Is this statement consistent with itself?

Finally, the nature of the crime should also be discussed.

A person wanting to buy drugs is not the same crime as someone selling drugs. The content of a message may indicate that the person is a drug user, but it may not necessarily indicate that they are a drug dealer.

This distinction between Article 188 and Article 191 of the Turkish Penal Code requires particularly careful consideration, as it carries extremely serious penal consequences.

Conclusion: WhatsApp messages are evidence; however, not every message is proof of conviction

In drug-related crimes, WhatsApp messages, SMS records, and phone calls are considered important evidence in criminal proceedings. However, the mere presence of a digital correspondence in a case file does not, by itself, prove that a person engaged in drug trafficking.

Firstly, the messages have been obtained lawfully . Data obtained through phone examinations that are contrary to the procedure stipulated in the Code of Criminal Procedure may constitute illegally obtained evidence. The 2024 decision of the 10th Criminal Chamber of the Supreme Court of Appeals, which held that WhatsApp messages obtained from a phone without the necessary decision or written order cannot be used as evidence in a judgment, even with the defendant's consent, is extremely important in this regard.

Secondly, the authenticity, completeness, and attribution of the messages to the suspect must be investigated.

The third and most important point is that the content of the messages must be evaluated together with other material evidence. In many decisions of the Supreme Court regarding drug trafficking, it has been found unlawful to establish a conviction based solely on telephone conversations when no drugs are found on the defendant, the substance mentioned in the conversations is not seized, the content of the telephone conversations is unclear, and the conversations are not supported by material evidence.

Therefore, the correct legal question in drug-related crimes is not "Is a WhatsApp message considered evidence?";

“Was this message obtained lawfully, does it truly belong to the defendant, can the content of the message be definitively determined, and has the connection between the message and drug trafficking been independently corroborated by material evidence?”

These are the questions.

Concluding that drug trafficking occurred based solely on a few WhatsApp messages without considering these circumstances could create serious legal problems in terms of the presumption of innocence, the principle of lawful evidence, and the principle that "the defendant benefits from the doubt.".

Frequently Asked Questions

Can WhatsApp messages be used as evidence in a drug case?

Yes. WhatsApp messages obtained legally can be considered as evidence.

Are WhatsApp messages alone sufficient grounds for conviction for drug trafficking?

Insufficient evidence is not always the case. Especially if the meaning of the messages is unclear and not supported by evidence of drug trafficking, financial transactions, physical surveillance, or other material evidence, the Supreme Court's practice may raise concerns about insufficient evidence for conviction.

Can the police look directly at the phone?

The examination of digital data contained in a telephone for forensic purposes is subject to the special procedures in the Code of Criminal Procedure. The 10th Criminal Chamber of the Supreme Court of Appeals has ruled that WhatsApp messages obtained from a telephone without the necessary court order or written warrant cannot be considered legally admissible evidence.

Can messages be viewed if the phone owner gives permission?

According to the Supreme Court's decision dated 2024, the mere consent of the individual does not substitute for the legal procedure stipulated in Article 134 of the Code of Criminal Procedure.

Does the presence of the words "goods" or "package" in messages prove drug trafficking?

The mere presence of these words should not be considered sufficient. It must be proven with concrete facts and material evidence that the words relate to narcotics.

Is it possible to impose a drug trafficking sentence based solely on messages, without seizing any drugs?

Each case is evaluated according to its own characteristics. However, in numerous decisions, the Court of Cassation has concluded that in the absence of drug seizure and the lack of supporting material evidence for telephone conversations, there is insufficient and conclusive evidence for conviction.

Could using WhatsApp conversations be effective in distinguishing between the crime of misuse of WhatsApp conversations and a trafficking crime?

Yes. The messages can provide evidence as to whether the person obtained the drugs for their own use or for the purpose of selling or supplying them to others. However, the nature of the crime must be determined based on the entire case file.