Is Witness Testimony Mandatory in Mobbing Claims? In light of the reviewed court decisions, the mandatory nature of witness evidence, the standard of proof, and the criteria courts use to evaluate this evidence in mobbing (psychological harassment) claims are presented below.

1. Mandatory Nature of Witness Testimony and the Right to a Fair Hearing In court decisions, there is no explicit provision stating that presenting a witness is a legal prerequisite (absolute necessity) for proving a mobbing claim. However, in the context of trial procedure and the right to present evidence, the following determinations have been made regarding the hearing of witnesses:

Court’s Obligation to Hear Witnesses: In the decision numbered 2019/571 E. of the General Assembly of Civil Chambers of the Supreme Court, if the party making the mobbing claim relies on witness evidence, it has been stated that the court is obligated to hear these witnesses. In the decision, with the statement “Since one of the consequences of psychological harassment is its negative effects on the psychology and personality of the victimized employee, the plaintiff’s witnesses must be heard,” the failure to hear witnesses was considered a violation of the right to a fair hearing.

Mandatory Nature in Administrative Investigations: In the decision numbered 2020/75 E. of the 12th Chamber of the Council of State, in administrative investigations concerning mobbing claims, the failure to refer to the statements of the witnesses presented by the plaintiff was ruled to render the investigation incomplete and the action unlawful.

2. Standard of Proof: Approximate Proof and Indication Higher courts, acknowledging the inherent difficulty of proving mobbing due to its nature, have adopted the principle of “approximate proof” instead of “absolute proof.” In this context, the role of witness statements is as follows:

Principle of Approximate Proof: In the decisions of the 10th Civil Chamber (2022/5692) and the 9th Civil Chamber (2022/8257) of the Court of Cassation, it has been emphasized that mobbing usually occurs between the perpetrator and the victim, and therefore “conclusive evidence beyond a reasonable doubt will not be sought.” Within the framework of the typical course of events and rules of experience, the existence of a “strong indication” supporting the employee’s claim is deemed sufficient.

Role of the Witness: The 22nd Civil Chamber of the Court of Cassation (2013/14296) stated that witness statements hold significant importance in labor law disputes. In the dissenting opinion to the decision, it was stated that due to the difficulty in documenting mobbing, basing the judgment largely on witness statements is a necessity.

3. Sufficiency of Witness Testimony and Its Relation to Other Evidence The mere existence of witness statements is not always considered sufficient for proving mobbing on its own; the quality of the statements and their consistency with other evidence are sought:

Requirement for Eyewitness Knowledge: In the decisions of the 9th Civil Chamber (2016/16456) and the 7th Civil Chamber (2013/11829) of the Court of Cassation, it has been ruled that if witnesses do not possess direct eyewitness knowledge and make statements based on hearsay, the claim of mobbing cannot be proven.

Consistency and Concretization: The Constitutional Court (15/11/2023) and the General Assembly of Civil Chambers of the Supreme Court (2015/461) have stated that if witness statements are not concretized by specifying the date, time, and place, the claim cannot be considered proven. The General Assembly of Civil Chambers overturned the local court’s resistance decision, which was based solely on witness statements, on the grounds that it “could not be proven with concrete evidence.”

Holistic Assessment: In the decisions of the 9th Civil Chamber of the Supreme Court (2022/6782) and (2022/8257), it was emphasized that witness statements should be evaluated together with health reports and medical documents. If the plaintiff gives up on presenting witnesses, it has been accepted that they have not fulfilled their burden of proof.

4. Additional Findings from Secondary Sources The following information has been compiled from the secondary details of the decisions and the approaches of different chambers of law:

Nature of Witnesses (Hostility Status): In the decision of the 22nd Civil Chamber of the Supreme Court (2017/25198), it was stated that the testimonies of witnesses who had lawsuits against their employer (hostile witnesses) were not considered sufficient on their own and needed to be supported by corroborating evidence.

Element of Systematics: In the decisions of the 4th Civil Chamber of the Supreme Court (2019/1136) and the 9th Civil Chamber of the Supreme Court (2023/4113), it was stated that witness statements must demonstrate that mobbing was carried out “systematically” and “continuously,” and that witnesses recounting isolated incidents are not sufficient to prove mobbing.

Ease of Proof: In the decisions of the 9th Civil Chamber of the Supreme Court of Appeals (2016/36185) and the 22nd Civil Chamber of the Supreme Court of Appeals (2014/2157), it was stated that the principle of “ease of proof” should be applied in favor of the employee in mobbing cases, and that corroborating witness testimonies (including those of the defendant’s witnesses) may be sufficient for proof.

Procedural Law Distinction: While the decision of the Antalya 4th Civil Court of Commerce (2019/194) reminds of the prohibition of proof by witness against a document in commercial cases, it is implicitly understood that this situation involves a different procedure than mobbing allegations in labor law, and that the way for hearing witnesses in mobbing cases is more open.

Conclusion: According to judicial decisions, while presenting a witness in a mobbing allegation is not a legal “condition of validity”;

Due to the difficulty of proof, it is practically the most important means of proof.

If requested by the parties, for the court to hear witnesses is a procedural necessity.

For witness statements to be taken as a basis for the judgment, they must be based on direct observation, consistent, and corroborating systematic pressure. A paper suggestion.

Why is Expert Lawyer Support Necessary?

Mobbing lawsuits are one of the most technical and sensitive types of cases, both in terms of **evidence structure** and the **law of evidence**. Especially in regions with intense working lives such as Istanbul, Tuzla, Pendik, Kartal, Maltepe, Kadıköy, Ataşehir, Ümraniye, Gebze, Dilovası, and Çayırova, identifying witnesses in mobbing allegations, substantiating statements, and presenting evidence in a holistic manner are of vital importance.

Therefore:

1. Professional Establishment of Witness Strategy is Required

It requires expertise to determine whether the witness has direct eyewitness knowledge, to which dates and events the statements will refer, and to take testimony without contradiction. Incorrect witness selection weakens the case.

2. The Mobbing Standard of Proof is a Technical Field

Issues such as prima facie evidence, circumstantial evidence, systematicity, psychological effects, and evidence correlation require specific legal knowledge. At this point, the guidance of an expert lawyer determines the fate of the case.

3. Proper Presentation of Documents and Medical Reports is Essential

Submitting witness statements to the case file in a manner consistent with health reports, performance records, and internal correspondence requires professional preparation.

4. Constitutional Court applications in allegations of rights violations require separate expertise

Mobbing can often become the subject of an individual application in the context of **Articles 17, 36, and 40 of the Constitution**. In Constitutional Court (AYM) applications, deadlines, procedure, and knowledge of jurisprudence are very critical.

In this context, 2M Law Office provides professional support with its technical expertise, command of case law, and regional experience in mobbing cases and individual application processes.