Role of Topic Shift and Violence of Grice Principles in Interrogation: Forensic Linguistics

Forensic linguistics is a new interdisciplinary branch of applied linguistics and law which utilizes language and linguistic evidence to analyze spoken and written texts technically. It helps police and judges to uncover the truth in lawsuits or proves the occurrence or non-occurrence of a crime in criminal cases in the courts. Discourse analysis is feasible using several tools and principles, including "Grice cooperative principles”. This study aims to show the role of changing the subject and violation of Grice cooperative principles in interrogations. That is, the accused seeks to prolong the duration of the investigation or provide incomplete information to the interrogator officer which consistently violates these strategies. On the other hand, the legal context and power relations do not allow the accused to change the subject according to his own desire or give irrelevant answers constantly. If this happens, it can be concluded that the accused tried to mislead the interrogator in linguistic terms. This research is a fieldwork study. After tens of observations of interrogations recorded in Tehran Police Bureau, the real samples were selected, classified and studied. The authors seek to introduce these principles and demonstrate their use in interrogations.