ILLEGALLY OBTAINED EVIDENCE

1. INTRODUCTION

Illegally obtained evidence refers to evidence collected using methods that do not comply with legal norms and the principles of fair trial. In this context, not only national legal regulations but also international legal norms must be considered. The primary goal in criminal procedure law is to obtain material truth, and this process must be conducted using lawfully obtained evidence. Article 38/6 of the Constitution stipulates that unlawfully obtained evidence cannot be used as evidence in court. Similarly, Article 217/2 of the Code of Criminal Procedure (CMK) states that the alleged crimes can only be proven with lawful evidence. Therefore, evidence obtained through unlawful means is disregarded in the judicial process and excluded from the case file.

2. OBTAINING UNLAWFUL EVIDENCE AND PROHIBITION ON EVALUATING UNLAWFUL EVIDENCE

Evidence obtained through unlawful means clearly violates the principles of fair trial. Evidence collected without explicit legal prohibition is also considered unlawful.

Article 38/6 of the Constitution stipulates that evidence obtained through unlawful means cannot be used as evidence. Similarly, Article 217/2 of the Code of Criminal Procedure (CMK) stipulates that only lawfully obtained evidence may be used as the basis for a verdict. These provisions are binding not only on judges but also on the prosecutor's office and law enforcement officers. Prosecutors and law enforcement officers are obligated to act lawfully during the evidence collection process. Since the majority of evidence in criminal proceedings is obtained during the investigation phase, law enforcement officers must meticulously follow legal procedures when collecting evidence.

For example, Articles 116 and subsequent articles of the Code of Criminal Procedure (CMK) clearly regulate search procedures. When law enforcement officers fail to comply with these regulations, the findings obtained are deemed unlawful and inadmissible as evidence. The requirement that search warrants be subject to judge approval is crucial for preventing arbitrary evidence collection. This point is frequently emphasized in Supreme Court precedents, which state that evidence obtained as a result of an unlawful search cannot be used against the defendant.

In addition, matters such as wiretapping, secret audio recording, and unauthorized acquisition of personal data also fall under the scope of unlawful evidence. Article 135 of the Code of Criminal Procedure (CMK) stipulates certain conditions for the detection and interception of communications. Information obtained through wiretapping or technical surveillance conducted without a court order constitutes unlawful evidence. According to established precedents of the Court of Cassation, unlawfully recorded phone conversations or secret recordings are not admissible as evidence in court.

Furthermore, statements obtained from a defendant or suspect through force, threats, pressure, or torture are also unlawful. Article 148 of the Criminal Procedure Code (CMK) stipulates that a suspect or defendant must not be subjected to pressure during the statement-taking and interrogation processes. The European Court of Human Rights (ECtHR) has also taken a strict stance on this matter, emphasizing that evidence obtained through torture and ill-treatment constitutes a human rights violation. In its Jalloh v. Germany decision, the ECtHR stated that evidence obtained by forcibly injecting substances into the defendant's body constitutes a human rights violation and that such practices should be prohibited.

Finally, evidence obtained through violations of privacy is also considered unlawful. Article 20 of the Constitution and Article 8 of the European Convention on Human Rights guarantee the protection of individuals' private lives. Evidence obtained through unlawful recording, wiretapping, or unauthorized access to personal data cannot be considered evidence in court.

Authorities conducting criminal proceedings are obligated to assess the legality of collected evidence. For evidence to be considered evidence, it must be directly related to the incident, consistent with material reality, and obtained lawfully. During investigation and prosecution processes, authorities are obligated to review the legality of evidence. If evidence is obtained unlawfully, it cannot be used as the basis for a verdict. This is known as the "prohibition on the evaluation of unlawful evidence." This prohibition has two important objectives: First, to ensure the legal security of individuals and protect human rights; second, to encourage law enforcement officers to act lawfully. If unlawful evidence is considered by the courts, it is impossible to speak of the legal security of individuals, and this leads to a consequence contrary to the principle of the rule of law. Law enforcement officers' obligation to collect lawful evidence aims to prevent arbitrariness in the evidence collection process. If evidence collected unlawfully is considered by the courts, a control mechanism cannot be established over law enforcement officers. Therefore, not evaluating evidence obtained through illegal means is one of the fundamental principles of the rule of law.

The law explicitly prohibits the consideration of unlawful evidence in court. For example, Article 148 of the Criminal Procedure Code (CMK) regulates the conditions under which a defendant's testimony must be taken. If the defendant testifies under torture, threat, or duress, the testimony is considered unlawful and cannot be used as evidence.

4. THE FRUIT OF THE POISONOUS TREE PRINCIPLE

The principle of "poisonous fruit of the poisonous tree"—developed in Anglo-American legal systems regarding the effect of unlawful evidence—states that unlawfully obtained evidence cannot be used, directly or indirectly, in a trial. This principle was established by Justice Frankfurter in the 1939 U.S. Supreme Court decision in Nardone v. United States.

Continental European legal systems also have various approaches to the impact of unlawful evidence. In Turkish law, this principle is a controversial issue when assessing the direct or indirect impact of unlawful evidence. While some legal scholars argue that this principle should be applied without exception, others argue that each specific case should be evaluated individually. Furthermore, the decisions of the European Court of Human Rights (ECtHR) provide for a strict oversight mechanism regarding the use of unlawful evidence. For example, in the case of Jalloh v. Germany, the ECtHR deemed the forced collection of evidence against the defendant's physical integrity a human rights violation and deemed the use of such evidence in court unlawful. Such decisions could also set a precedent in the Turkish legal system.

5. CONCLUSION

In criminal proceedings, the use of legally obtained evidence is mandatory to establish material truth. Article 38/6 of the Constitution and Articles 217/2 and 206 of the Code of Criminal Procedure explicitly prohibit the use of unlawful evidence as evidence in court.

In accordance with these provisions, unlawful evidence cannot be used either against or in favor of the defendant. Furthermore, there is an absolute prohibition on the use of unlawfully obtained evidence as the basis for a verdict. This prohibition is crucial for protecting the right to a fair trial, ensuring legal certainty for individuals, and preventing arbitrary actions by law enforcement. Consequently, the exclusion of unlawfully obtained evidence is a principle that both protects individual rights and strengthens the rule of law.

SOURCE:

Turkish Constitution

Code of Criminal Procedure no. 5271