While there is a substantial research literature on Western ‘foreign fighters’ – those young men and women from Europe, North America, Australia and elsewhere who traveled to Syria and Iraq, from around 2011–2017, to join jihadist groups engaged in combat – there is a dearth of comparative studies examining the backgrounds of these fighters. National variations in the levels of recruitment have been measured and samples examined to determine the demographics of these fighters, indicating some national variations in who went, how, and maybe why. More fulsome comparative data is needed, however, to detect and measure such differences to gain insight into the factors conditioning the radicalization of these foreign fighters. Calling on original and unique datasets, this study presents the results of a comparative analysis of Canadian and Swedish foreign fighters. In each case the findings are compared with other domestic jihadists as well to delineate if those drawn to fight in Syria and Iraq differ. Clear differences emerge in the basic demographics of these national samples, highlighting some empirical and interpretive issues in need of further analysis.

In recent years, the study of terrorism and violent extremism has increasingly benefited from the use of register data such as population data and judicial data. The use of this type of data brings with it many advantages, such as the ability to study complete populations, to combine different sources of data, and, often, it enables researchers to take on a longitudinal and comparative approach. However, the use of register data also brings with it some significant challenges, in terms of acquiring the data (practical challenges) and in terms of biases in the data (content/ethical challenges). In this paper we discuss the usage of register data in terrorism research, with a focus on the Dutch and Swedish context. Whereas both countries are to some extent similar in that they both have a rich data-infrastructure, differences also exist regarding the type of data, agencies responsible for collecting and distributing the data, and ethical approaches. In the chapter, we will go into the strengths and weaknesses of using register data in research on terrorism and violent extremism. Moreover, we will elaborate on how the use of register data can be improved, what type of research questions can and cannot be answered based on register data, and on potential opportunities of integrating register data into mixed-methods designs.

In this study we investigate organized crime by studying the degree of criminal organization. We use population-level register data on criminal suspicions between 2011 and 2016 to analyze the territoriality of Swedish street gangs in terms of geographical mobility, their collaboration in crime through their co-offending network's clustering and community structure, and their crime versatility. Although Swedish street gangs exhibit varying degrees of geographical mobility and criminal collaboration, overall, they have limited reach along these dimensions, characterized by low clustering and limited crime specialization. Violence seems to become a necessary tool only when a gang reaches a certain degree of organization. By unbraiding criminal mobility and its association with other organizational elements such as criminal collaboration in different settings, we provide insights into the structure and dynamics of criminal organizations and contribute to a richer understanding and conceptualization of how crime is organized.

In this exploratory study, individuals’ processes of engagement in violent extremist groups are analysed by drawing from criminological life-course theory and narrative-based understandings of crime. Based on interviews with individuals who have participated in violent extremism, it is suggested that the process of engagement consists of three steps: (1) a weakening of informal social controls, followed by (2) an interaction with individuals in proximity to the group and (3) a stage of meaning-making in relation to the group and one’s identity, resulting in an individual’s willingness and capacity to engaging in the group’s activities, including violence. In future theorizing about processes of engagement in violent extremism, the meanings of age, and the life-course stages of late adolescence and emerging adulthood in particular, should be given analytic attention.

Hand grenade attacks have increasingly been reported in Sweden. However, to date no research on the topic exists. The present study aims to describe the illegal use of hand grenades and to test its spatio-temporal relationship with gun violence to explore whether the two forms of violence are connected. Data were collected for the years 2011 to 2016 from the Swedish police and from open sources about hand grenade detonations, which were considered alongside shootings as two types of violence commonly attributed to criminal groups. Descriptive data and trends are presented and spatio-temporal analysis of near-repeat patterns was performed using a near-repeat calculator. All in all, there were 77 incidents of detonated hand grenades in Sweden during the six-year observation period, in which nine individuals were injured and one killed. The number of incidents increased, with about half of the them occurring during the last year. A near-repeat analysis was performed on shootings (N = 1048) and hand grenades (N = 55) in Stockholm, Gothenburg and Malmo. The shootings exhibit a strong component of near-repeat patterns, but adding hand grenades to the analysis did not strengthen the patterns, suggesting that the two types of violence only partially share spatio-temporal patterns. The study confirms an increase in the use of hand grenades in Sweden, although the reason for the increase is unknown. The increase does fit with the overall changing pattern in violence in urban areas in Sweden, which broadly tends to be attributed to criminal groups in disadvantaged neighbourhoods.