What Happens if the Police Find Evidence of Another Crime During a Search? Incidental Evidence and Complaint-Dependent Offenses in Turkey

A search warrant is generally issued for a specific offense, a specific address and a specific purpose. In practice, however, law enforcement officers may come across traces of an entirely different offense unrelated to the crime they were searching for. This situation raises serious procedural questions both for the prosecutor's office conducting the investigation and for the suspect: Can this new evidence be used? Is a new search warrant required? And what if the offense discovered is of a kind that can only be investigated upon the victim's complaint (a complaint-dependent offense) — how does the process work then?

In this article, we explain this institution, known in Turkish criminal procedure law as "incidental evidence" (tesadüfi delil), within a concrete framework that may also arise in everyday life, based on the relevant legislation and settled case law of the Yargıtay (Court of Cassation).

Why Does This Matter?

Encountering unexpected evidence during a search can arise not only in organized crime files but also in relatively common complaint-dependent offenses such as the sale of counterfeit goods, insult, or breach of trade secrets. For example, a search conducted within a fraud investigation may uncover an entirely unrelated trademark infringement (counterfeit goods). A wrong step at this point can render the evidence entirely worthless and expose the law enforcement officers themselves to a separate legal risk (an allegation of unlawful search).

Summary of the Situation (A General Scenario)

Suppose a search warrant is duly issued within an investigation file and the police carry out a search at the specified address. During the search, they find concrete evidence that another offense (for example, a complaint-dependent one) has been committed, with no connection whatsoever to the offense in the file. What should the officers do?

A frequently encountered example in practice is a search for counterfeit products (trademark infringement) during which counterfeit goods bearing other brands — never mentioned in the search warrant — are also found. The courts have assessed such situations repeatedly, and the general principles have become clear.

The Point of Legal Dispute

At the root of the problem lies this question: when the police encounter evidence of an offense other than the one they were assigned to search for, may they seize it on their own initiative, or must a separate procedure be followed? And if that offense is complaint-dependent (i.e., the prosecutor's office cannot act ex officio without the victim's complaint), is the preservation of the evidence affected?

What Does the Legislation Say?

• Article 138/1 of the Turkish Code of Criminal Procedure (CMK, Law No. 5271): If, during a search or seizure, evidence is found that is unrelated to the ongoing investigation but raises suspicion of another offense, that evidence is immediately taken into safekeeping and the situation is reported to the public prosecutor's office.
• Article 10 of the Regulation on Judicial and Preventive Searches: Following this notification, a new written order must be requested from the prosecutor in order to actually seize the evidence. If the prosecutor cannot be reached, the action may be taken on the written order of the law enforcement supervisor; however, this action must be submitted for judge's approval within 24 hours, and the judge must announce their decision within 48 hours. Otherwise, the seizure is automatically lifted.

One important point: the legislation makes no distinction based on the type of offense the evidence relates to (whether or not it is complaint-dependent). In other words, "this offense is complaint-dependent anyway and there is no complainant, so let's ignore it" is not an option available to the police.

What Does the Court of Cassation Say?

The case law of the Court of Cassation has clarified the matter along several main lines:

• Duty to preserve and report: In a decision of the Yargıtay Assembly of Criminal Chambers dated 2019 (E. 2016/75, K. 2019/18) and a decision of the Yargıtay 19th Criminal Chamber dated 2019 (E. 2019/23971, K. 2019/7747), the incidental discovery, during a trademark search, of counterfeit goods bearing other brands, and the preservation of that evidence on the prosecutor's instruction followed by approval by the criminal judgeship of peace, were found lawful. When the rights holders subsequently filed complaints, prosecutions could be brought based on that evidence. A similar assessment appears in a decision of the İzmir Regional Court of Appeal 16th Criminal Chamber dated 2020 (E. 2019/1738, K. 2020/1876).
• A new written order and judge's approval are mandatory: In a decision of the Yargıtay 9th Criminal Chamber dated 2023 (E. 2022/9487, K. 2023/8809), a seizure carried out for evidence found on suspicion of an entirely different offense, without obtaining a new written order and without submitting it for judge's approval, was found unlawful, and it was held that an acquittal should be entered. A decision of the Yargıtay 12th Criminal Chamber dated 2024 (E. 2020/12020, K. 2024/2056) likewise treated a similar procedural defect as a ground for reversal.
• The lawfulness of the original search is a precondition: In the decisions of the Yargıtay 21st Criminal Chamber (T. 2016, E. 2015/5742, K. 2016/2217) and the Yargıtay 8th Criminal Chamber (T. 2016, E. 2015/12885, K. 2016/7615), it was emphasized that if the initial search itself was irregular, the "incidental" evidence found during it will also be deemed unlawful. In other words, the protection afforded to incidental evidence can only be built on a clean search.
• There is no catalogue-offense limitation: A decision of the Yargıtay Assembly of Criminal Chambers dated 2020 (E. 2016/944, K. 2020/513) and a decision of the Yargıtay 11th Criminal Chamber dated 2025 (E. 2021/12439, K. 2025/2663) confirmed that the "catalogue offense" limitation applicable to the interception of communications does not exist for search and seizure measures; incidental evidence of any offense subject to the general provisions (including complaint-dependent ones) may be assessed within this framework.

Points to Watch Out For

The critical points a lawyer or an interested party should check in such a file are:

• Was the initial search warrant lawful? If not, everything built upon it is tainted.
• Was the evidence truly found "incidentally"? If the police exceeded the limits of the original offense and conducted a systematic "fishing expedition," the evidence found cannot benefit from the incidental-evidence protection.
• Was a new written order obtained? The existing search warrant is not sufficient for seizing incidentally found evidence; a new written order is absolutely required.
• Were the judge-approval time limits (24/48 hours) observed? If these deadlines are missed, the seizure is automatically lifted.
• Was the complaint requirement satisfied? If the offense is complaint-dependent, the prosecutor's office must first locate the victim and establish their intent to complain. If the right to complain is not exercised within the complaint period (generally 6 months), the evidence must be returned to its owner and the file closed.

Conclusion: What Should You Do?

The incidental discovery, during another search, of evidence relating to a complaint-dependent offense does not automatically invalidate that evidence; but neither does it automatically make it valid. What is decisive is whether the procedure was properly followed.

• If you are in the position of suspect or defendant: have your file checked to see whether a new written order and judge's approval exist; if there is a defect, this may mean the evidence cannot form the basis of the judgment.
• If you are in the position of victim/complainant: monitor whether your right to complain was duly notified to you, and keep track of the statutory complaint period.
• In either case, consulting a criminal lawyer without delay on these technical procedural issues can substantially change the fate of the evidence and the strategy of the case.