Operation Heron: latent topic changes in an abusive letter series

The paper presents a two-part forensic linguistic analysis of an historic collection abuse letters, sent to individuals in the public eye and individuals’ private homes between 2007 2009. We employ technique structural topic modelling (stm) identify distinctions core topics gauging value this relatively under-used methodology linguistics. Four key were identified ‘Politics A’ ‘B’, ‘Healthcare’ ‘Immigration’, their coherence, correlation shifts evaluated. Following stm, qualitative corpus was undertaken, coding concordance lines according topic, with reliability coders tested. This demonstrated that various connected statements within same tend gain or lose prevalence over time, ultimately confirmed consistency content four through stm throughout letter series. discussion conclusions reflect on findings also consider utility these methodologies for linguistics particular. study demonstrates real revisiting dataset such as test develop field.