Expert Analysis of Testimony Credibility

Few people know that linguistic analysis methods are used in criminal investigations to assess the completeness and credibility of testimonies. Most often, this occurs during a psychological-linguistic expert examination, which includes a comparative analysis of statements made by one or more individuals. To initiate this process, it is sufficient to ask the expert a question that requires the creation and subsequent analysis of a comparative table of the testimonies of the case participants. For example:

How do the statements of witness …, previously given and recorded in the witness interrogation protocol dated (interrogation date), compare with their statements contained in the explanation dated (interrogation date), as well as with the statements given during the on-site verification?

All case materials related to the incident under investigation and describing the same event are suitable for analysis. When compiling a comparative table of case materials, the expert identifies common points, compares them both collectively and individually, and pays attention to the syntactic and lexical features of the text. Often, this is enough to draw conclusions that can later influence the outcome of the investigation.

Case Example: Comparative Analysis of Testimony

For instance, during the comparative analysis of the testimony of victim K., investigative protocols and written statements by K. from the case materials were used. K. claimed to be a victim of fraud. Her statements to the investigator were complex in structure and interspersed with lyrical digressions and emotional descriptions, making it difficult to extract factual material for analysis. When comparing thematically significant segments for the investigation, a comparative table was created, revealing some significant discrepancies and inconsistencies in the victim’s statements, specifically:

• The victim gave different reasons for giving money to the witness: in the “Explanation” dated 10/10/2017, she stated she gave money for repairs, while during an additional interrogation on 07/10/2018, she said N. asked her for money to keep at home, fearing illegal actions by her son.
• The victim mentioned different numbers of missing jewelry items and described them differently.
• The victim made various material claims, gradually adding to the initial 300,000 rubles additional amounts and accusations of jewelry theft.

During the comprehensive psychological-linguistic examination of the victim’s testimony, experts concluded that the statements about the investigated event had been deliberately edited and memorized, based in part on the significant discrepancies found.

Comparative Analysis of Multiple Participants

It is important to note that the analysis is conducted not only on the statements of a single individual but also on those of participants with different statuses in the same case, or groups of defendants. For example, when compiling a comparative table of the testimonies of two suspects (a man and a woman) under Article 158 of the Criminal Code (theft), it was found that the suspect’s statements, recorded at different times, were not identical in content and contained some discrepancies. Notably, the male suspect described in detail how the victim searched for money, which the female suspect denied. Additionally, the male suspect referred to “some white piece of paper,” while the female suspect described it as “a flyer that looked like a banknote.” The expert found it unusual that the victim “did not examine the flyer,” even though she said it resembled a 5,000-ruble bill. Such a description suggests the female suspect’s explanation was unreliable. Similarly, the male suspect claimed he was unaware of the situation with the found banknote, yet repeatedly described how his wife saw “a piece of paper that looked like a banknote,” while the female suspect stated they argued because she threw away the paper.

By analyzing the overall structure of the responses, the expert can determine how well the participants orient themselves in time intervals and their knowledge of the location. However, only through close comparison can minor inconsistencies be identified, not only between the testimonies of different participants but also within each individual’s own statements. These discrepancies may be minor, relating to the positions of participants relative to each other, their actions, or the content of conversations. All of this helps address the questions posed for investigation within the framework of a comprehensive psychological-linguistic expert examination.