The content of the article aims to acquaint the reader with the current trends in the field of counter-terrorism and counter-extremism from the perspective of a member of the newly established special national unit of the Police of the Czech Republic, Criminal Police and Investigation Service, and from the perspective of an academic employee of the Police Academy of the Czech Republic in Prague, with an emphasis on the current understanding of criminalistic tactics and investigation methodology, based on the knowledge of research activities conducted within the research programme of the university and the practical experience of a member of a specialised police unit responsible for the documentation of the most serious crimes in the described area. At the same time, the newly established unit with substantive Bezpečnostní teorie a praxe 2/2024 84 responsibility for the detection and investigation of terrorism, extremism, and cybercrime is introduced.