Presupposition as investigator certainty in a police interrogation: The case of Lorenzo Montoya’s false confession

This article presents an analysis of the use by police investigators of presupposition-bearing questions (PBQs) in interrogation as a process for communicating certainty of guilt. Among the techniques of interrogational maximization employed by police is the communication to the suspect of the interrogators’ certainty of the suspect’s guilt. While social science research notes that such communication of certainty is given directly, for example by statements that they ‘know’ the suspect is guilty or by direct accusations such as ‘you did it’, this analysis shows that certainty of guilt can also be communicated by presuppositions embedded in interrogation questions. Discourse analysis of the complete transcript of the interrogation of a 14-year-old suspect reveals further that through the use of 117 PBQs, interrogators are able to accrue inadvertent admissions to three crucial global ‘facts’ about the suspect’s involvement in the crime – each of which is composed of multiple subsidiary ‘facts’. In addition to identifying the role of PBQs in eliciting inadvertent admissions, the analysis also notes how PBQs serve as ‘a powerful instrument in the implicit assertion of debatable propositions’ as part of the interrogational record.