By Carola García-Calvo and Fernando Reinares*
Spain has not been exempt from the unprecedented jihadist mobilization worldwide prompted by the Islamic State (IS) organization, though Spain is not among the Western European countries most affected, neither in absolute terms nor relative to the size of its population. Between June 2013, when the first anti-IS (then still anti-ISIL) counterterrorism operation was launched inside Spain, and August 2016, the total number of detainees for IS-related terrorist activities was 130. Until the Summer of 2016, some 190 departed from Spain to join the ranks of IS in both Syria and Iraq as foreign fighters. Six of the latter were arrested upon return–though the actual number of returnees can be estimated as being up to five times larger–and are included in the figure of detainees.
To explore patterns of involvement at the individual level of analysis, we have gathered information and built a database on 130 detainees, in the Elcano Database on Jihadists in Spain (EDBJS). Our sources were the Interior Ministry’s press releases, police reports and publicly accessible court documents at the Audiencia Nacional (National Court) in Madrid, the only jurisdiction in Spain dealing with terrorism offences. Our database has also benefitted from interviews with law enforcement experts and information gathered from systematic searches of media sources indexed in Factiva. The body of information assembled was thus treated both quantitatively and qualitatively.
Most individuals arrested in Spain for IS-related terrorist activities are men (83.8%) aged between 20 and 44 at the time of detention (80.3%), more often than not–56.7%–they were married. 43% are nationals of Spain and 41.4% are Moroccan nationals. Five out of every ten are immigrants and four out of ten are second generation descendants of (mainly) Moroccan immigrants. Some 13.3% are converts. Six out of ten were enrolled in secondary education, twice the number of those who only attended primary school. Three times as many as those detainees with only working class jobs, have been in middle class or lower middle class jobs. 16.7% had no known occupation at the time of detention, and one third had a previous criminal record as ordinary delinquents.
In Spain, just like elsewhere, different patterns of becoming involved in IS-related activities can be observed; this affects the range of expressions a terrorist threat may eventually adopt. In this sense, becoming involved as an individual acting alone is not the same as becoming involved with others as part of cells, groups and networks (CGN). In this article we will explore how exactly the 130 individuals arrested in Spain for IS-related terrorist offences became involved. We also look at the position they occupied inside the CGN most of them belonged to. We will explore the nature, size, composition, scope and functions of the CGN these detainees joined. Finally, we will also look how many of them were willing to become foreign fighters or to carry out attacks in Spain, the two options being not mutually exclusive.
Modalities of Involvement and Position of Individuals in Cells, Groups and Networks (CGN)
Only 4.6% of all those arrested in Spain for IS-related terrorist activities since 2013 became involved alone, i.e. isolated from other jihadists; they were literally lone actors, not just single actors (Table 1). When lone actors eventually plot or execute attacks, they are often referred to as “lone wolves”. This epithet is used to label those self-radicalized jihadists who act independently and solely at their own initiative. However, in the case of Spain, the small number of detainees who qualify as lone actors were above all dedicated to the exaltation of IS and the spreading of its propaganda via the internet and the social media. Among them, two intended to travel to Syria and join the ranks of IS, whereupon they would have ceased being lone actors. Interestingly, we found no women among lone actors.
Table 1: Individuals arrested in Spain for IS-related terrorist activities (June 2013-August 2016) by sex and modality of involvement (%)
Modality of involvement
Source: Elcano Database on Jihadists in Spain (EDBJS).
It should certainly not be overlooked that IS-inspired individuals involved as lone actors pose a potential threat to Western societies, Spain included. IS’s leadership, as its well known, has made repeated calls for terrorist acts by individual supporters difficult for police and intelligence services to detect and arrest. The limited presence of such individuals among the detainees in our database of 130 cases might therefore misrepresent their actual relevance. Be that as it may, fact remains that 95.4% of all those detained in Spain during that period involved those who were in the company of others, i.e. members of CGN.
This statistical distribution of all the mentioned detainees according to their modality of involvement shows a remarkable continuity when compared with those of individuals convicted in Spain for jihadist terrorism offences or who died as a result of acts of suicide terrorism over the preceding nine years. Between 2004 and 2012, exactly 5% of these became involved on their own, as lone actors. On the other hand, 95% were involved as members of cells and small groups, sometimes connected with jihadist organisations abroad (primarily in South Asia, the Middle East and North Africa) though, on other occasions, they operated independently from such entities.
Whether involved on their own as lone actors, or in the company of others, as part of CGN, all the detainees included in our database had as their organization of reference Islamic State of Iraq and Levant (ISIL) or its successor IS. However, about a quarter of them, for some time prior to aligning with ISIL (later IS), initially had the Al-Nusra Front (Jabhat al-Nusra) as their jihadist organization of reference. This is a common pattern among Western European foreign fighters, the French Cannes-Torcy network being one case in point.
Focusing on individuals arrested in Spain for IS-related terrorist activities who became involved in the company of others – the overwhelming majority — it is remarkable that 77.9% were integrated into CGN that had some kind of organizational link with IS at different levels of IS’ structure. The remaining 22.1% were members of jihadist CGN that were merely inspired by IS’ ideology and propaganda (Table 2). In contrast to the men, of whom some (26.9%) only had lose ideological affiliations, all women in the dataset were part of CGN, interacting in one way or the other with IS.
Table 2: Individuals arrested in Spain for IS-related terrorist activities (June 2013-August 2016) involved with others, by sex and type of link with the jihadist organization of their CGN (%)
Modality of involvement
Detainees in Spain for IS-related terrorist activities who participated in CGN occupied different position inside such ensembles. For the purpose of this article we distinguish, inside each CGN, between centre or first-tier, intermediate circles or second-tier, and periphery. Individuals in the first-tier were mainly devoting themselves to leadership, coordination and indoctrination tasks. Individuals of the second-tier undertook a diverse range of functions, including engaging in preparations to become foreign fighters. Individuals in the periphery of their corresponding CGN were basically recruited with the purpose of turning them into foreign fighters.
Accordingly, 26.7% of all those individuals arrested in Spain between June 2013 and August 2016 for IS-related terrorist activities who were involved in the company of others were located in the first-tier of their corresponding CGN. Another 51.5% of them were located in second-tier circles; exactly half of them were preparing their own journeys to Syria and Iraq. The remaining 21.8% were located in the periphery of the CGN to which they belonged (Table 3).
Table 3: Individuals arrested in Spain for IS-related terrorist activities (June 2013-August 2016) involved with others, by position in their CGN (%)
Missing data: 23
Consistent with the tasks performed in the core, prominent among detainees having central positions were men aged in the average between 34 and 35. They were mainly of Spanish nationality and had typically worked in the tertiary (service) sector of the Spanish economy or were unemployed. Individuals arrested who were positioned in the centre of the CGN to which their belonged came across as better informed about the Islamic creed–in a Salafist version- and Sharia law than those placed in the other two tiers. Their knowledge about the Salafist interpretation of Islam could be considered relevant in just a quarter of the cases.
Even though men dominate the second-tier of CGN, the percentage of women increases in this intermediate positions fourfold when compared to the first-tier. Individuals in this second-tier were also five years younger than those in the first-tier, with an average age of 29.2. Those detainees positioned in the second-tier were mostly Spanish nationals, most of them unemployed or working in the service sector, having a rather rudimentary knowledge of the the Salafist interpretation of Islam and its corresponding notion of sharia law.
In the periphery, men also predominated although here women accounted for one third, which means an eightfold increase compared to the first-tier and a doubling with respect to the second-tier. Consistent with the aim of becoming foreign fighters, the average age of detainees who were placed in the periphery was 23, that is to say, eleven years younger than those in the first-tier or inner circle and six years below that of the second-tier. Those in the periphery were mainly of Moroccan nationality, many of them unemployed or students and not well-informed about Islam and sharia.
Detainees by Nature, Size, Composition and Scope of their CGN
64% of all those detained in Spain for IS-related activities over the three-year period beginning in June 2013 were active as members of newly formed CGN (Table 4). That is to say, cells, groups or networks established from 2011 onwards – after the outbreak of the civil war in Syria – gathering individuals with no previous involvement in jihadist activities. The remaining 36% of these detainees were, by contrast, part of CGN which may be described as of a regenerated nature. The latter can be differed from the former by the fact that at least one member had been involved in jihadist activities in the country prior to the current mobilization over Syria and Iraq.
Table 4: Individuals arrested in Spain for IS-related terrorist activities (June 2013-August 2016) involved with others, by nature of their CGN (%)
Missing data: 35
The number of detainees who belonged to CGN allows us to tentatively estimate the size of these jihadist aggregates by distributing them according to the total number of individuals arrested in Spain for IS-related terrorist activities, between June 2013 and August 2016, who belonged to the same cell, group or network. Following this approach, four of every 10 (43.6%) were apparently part of rather extensive CGN whereas three out of every 10 seemed to have been integrated in, respectively, medium-size (27.4%) and small-size (the remaining 29%)— size cells, groups and networks (Table 5).
Table 5: Individuals arrested in Spain for IS-related terrorist activities (June 2013-August 2016) involved with others, by total number of detainees from their same CGN (%)
Detainees from same CGN
8 or more detainees
Between 4 and 7 detainees
Up to 3 detainees
Observing the different nationalities existing among the individuals arrested who were part of the same CGN makes it possible to assess the degree of internal homogeneity or heterogeneity of these aggregates. With this in mind, we distributed these individuals according to the nationalities of the detainees who were members of the same CGN. There are detainees who were part of the same CGN and shared only one nationality, detainees part of the same CGN but predominantly – over 75% – from one nationality, detainees part of the same CGN but mixed in terms of nationalities, even if the majority – between 50% and 74% – were having the same, and finally detainees who were part of the same CGN but with more diverse nationalities.
As we can see, individuals arrested in Spain for IS-related terrorist activities who, based on data about fellow detainees from the same jihadist aggregate, appear to have belonged to rather heterogeneous CGN, account for slightly over half of the total. The highest percentage were apparently integrated into mixed CGN, with the majority of them being Moroccan nationals (Table 6). Detainees who had no less than three quarters of its members composed by nationals of Spain became particularly salient among those individuals who had joined more homogeneous aggregates.
Table 6: Individuals arrested in Spain for IS-related terrorist activities (June 2013-August 2016) involved with others, by nationalities among detainees of same CGN (%)
Nationalities among detainees from same CGN
All Spanish nationals
Predominantly Spanish nationals
Predominantly Moroccan nationals
Mixed with majority of Spanish
Mixed with majority of Moroccan
Mixed with other composition
Source: EDBJS. Note: Table includes data only about individuals belonging to middle and large size CGN
Meanwhile, no more than 31.1% of all the detainees who became involved as part of CGN were actually part of cells, groups and networks confined to the Spanish territory (Table 7). On the contrary, the vast majority of those individuals who became involved in the company of others (exactly, 68.9%), belonged to CGN that operated in two or more countries and were therefore transnational in scope.
Table 7: Individuals arrested in Spain for IS-related terrorist activities (June 2013-August 2016) involved with others, by scope of their CGN (%)
Detainees from same CGN
Missing data: 18
For nearly eight out of 10 of the latter (75.7%) the transnational links of their CGN extended to Morocco, specifically to northern places such as Tetouan, Fnideq or Nador, all of which are close to the Spanish enclaves of Ceuta and Melilla as well as to peninsular Spain (Table 8). For almost half of the same subset of detainees (47.1%) transnational links extended as far as Turkey. Lower figures correspond to Tunisia (21.4%) and Egypt (12.9%), with Libya, Mali and Indonesia each amounting to 8.6%. Turkey was, however, the real transit country on the way to Syria and Iraq for the foreign fighters originating from Spain. Turkey is also where Spanish jihadists related to IS had placed delegates, or benefitted from the help of IS facilitators who received them, provided them with accommodation, and helped them cross the border into the ‘Caliphate’.
For nearly four out of 10 in the same subset of detainees (37.1%), the transnational CGN they belonged to had links to Belgium, and for about two out of 10 (22.9%) to France–both countries in which their jihadist ensembles had at least one member. It was precisely in France and Belgium that IS established the operational network whose members planned and executed the concatenated attacks of 13 November 2015 in Paris, and of 22 March 2016 in Brussels.
Table 8: Individuals arrested in Spain for IS-related terrorist activities (June 2013-August 2016)
by geographical scope of their transnational CGN (%)
Detainees from same CGN
Outside Western Europe
Inside Western Europe
Missing data: 3
It is worth mentioning, in this respect, that two of the detainees in Spain had links with the IS Paris-Brussels network. One of them, with dual Algerian and French nationality, but living in France, was arrested in Almería on April 2014. He was related to a purported operational head of IS’ operations in Europe, Salim Benghalem. Another, himself resident of Torrevieja in the province of Alicante, who joined up with IS in Syria in 2014, was arrested in Warsaw in June 2015 and subsequently handed over to the Spanish authorities. Abdelhamid Abaaoud, the presumed ringleader of the 13 November terrorists, had ordered him to return to Europe after receiving training in the use of arms and explosives.
Detainees According to the Diverse Functions of Their CGN
The cells, groups and networks within which most individuals arrested in Spain were integrated, performed a wide variety of overlapping functions. As a whole, 95% of these detainees, were part of CGN focusing on radicalisation and recruitment tasks (Table 9). Moreover, some 74.8% were part of CGN sending foreign fighters to Syria and Iraq. These are the highest percentages found for this set of detainees who became active as jihadists in the company of other fellow militants.
We also found that women tended to be concentrated precisely in those CGN that focussed on radicalisation, recruitment and the dispatch of foreign fighters. This reflects the fact that women arrested in Spain for IS-related activities were mainly performing such tasks via social media. However, while women had taken on an active role in this domain, it was still men who formed the core leadership of the CGN they were part of–something clearly exemplified by of one of the most important jihadist congeries dismantled in Spain by the police as a result of Operation Kibera.
Table 9: Individuals arrested in Spain for IS-related terrorist activities (June 2013-August 2016) involved with others, by sex and the functions of their CGN (%)
Sent foreign terrorist fighters
Exaltation of terrorism
60.5% of detainees involved with others were part of CGN which carried out financing tasks. Existing information suggests that they basically obtained money to cover their own economic needs, derived from their involvement. To raise money they benefited from donations and collections held in neighbourhoods such as Príncipe Alfonso in Ceuta, or in places of worship such as the M-30 Mosque in Madrid. However small-scale drug trafficking was also a source of income. The members of one cell dismantled in spring 2015 in the province of Barcelona planned other forms of fund-raising, such as kidnapping for ransom, or creating a cultural association that would allow them to apply for subsidies.
By contrast, two individuals were arrested in Girona, on July 2016, because of the money remittances they had sent to IS, by means of designated intermediaries located in Turkey, and following instructions from IS. In addition to contributing half of their personal monthly income, they relied on crowdfunding through Internet, asking fellow Muslims who were unwilling to migrate to Syria and Iraq themselves for an economic contribution to jihad, usually small quantities of between 50 and 100 Euro. In order to transfer funds, just like in the case of a network offering logistic support to IS whose members were arrested on February 2016 in the provinces of Alicante and Valencia, and in Ceuta, they resorted to international money transfer companies, or money service business, using intermediaries, or the traditional hawala method.
56.3% of the detainees were active within CGN whose members distributed IS propaganda. In some cases, they simply disseminated propaganda created by the jihadist organisation’s media platforms. In other cases, such as with a network whose members were arrested in March 2015 in the provinces of Ávila, Ciudad Real, Barcelona and Girona, they translated the content generated by IS media outlets into Spanish. However they also produced content of their own which was more accessible to the offspring of immigrants or young Moroccans resident in Spain.
Especially significant, however, in terms of the threat that IS poses to Spain, is the evidence that, of all the detainees 33.6% belonged to CGN with operational capabilities. Significant in this same respect is also the fact that 31.9% of them were members of CGN that undertook terrorist training activities on Spanish soil. Moreover, similarly about one third had joined CGN which were willing to launch attacks within Spain.
From Radicalised Muslims in Spain to Foreign Fighters in Syria
No less than six out of every 10 individuals arrested in Spain for IS-related terrorist activities between June 2013 and August 2016–exactly 63.2% of all detainees–had either travelled to Syria and Iraq, had tried to travel, or had the intention of doing so (Table 10). Remarkably, women appeared more likely to travel and join IS ranks abroad than men. While nearly nine out of every 10 detainee women had either travelled to these conflict zones, had tried to travel there, or intended to travel, the same holds true for no more than 6 out of every 10 detainee men. Those women responded positively to the explicit call from Abu Bakr al-Baghdadi to settle in the ‘Caliphate’ and contribute to its consolidation and expansion.
Table 10: Individuals arrested in Spain for IS-related terrorist activities (June 2013-August 2016) who had travelled to conflict zones, tried to travel, or had intention of travelling, by sex (%)
Detainees who had travelled to combat zones, had tried to
or had the intention of travelling
As anticipated, detainees involved with others inside CGN were also more likely to travel abroad and join the IS ranks if located in their periphery (76.5%) than if placed in intermediate (65.2) or core (56.6) positions (Table 11). Even when, more often than not, detainees in the first and second tiers had travelled to Syria and Iraq, tried to travel or had the intention of travelling, they devoted much of their efforts at radicalising and recruiting, sometimes even training, individuals with the specific purpose of turning them into foreign fighters.
Table 11: Individuals arrested in Spain for IS-related terrorist activities (June 2013-August 2016) who had travelled to conflict zones, tried to travel, or had intention of travelling, by position in their CGN (%)
Detainees who had travelled to combat zones,
had tried to or had the intention of travelling
A large majority of detainees part of CGN who had travelled to conflict zones, had tried to or had the intention of doing so were actually arrested by Spain’s police agencies before they reached Syria, Iraq and, exceptionally, other IS-related destinations (Table 12). Most underwent detention while already decided to make the journey, while they were preparing for it, at the point of embarking upon it, or even in transit. About one out of every 10 (9%), were arrested on their return (Table 12). Interestingly, the percentage of women arrested while in transit (42.9%) is particularly salient and nearly multiplies by four the figure observed for men (11.3%).
Table 12: Individuals arrested in Spain for IS-related terrorist activities (June 2013-August 2016) who had travelled to conflict zones, had tried to or had the intention of doing so, by sex and stage of travel at the time of detention (%)
Willing to travel
Preparing to travel
As many as 76.3% of these detainees that became or intended to become foreign fighters for IS had at their disposal, inside Spain, a network facilitating their journeys to the ‘Caliphate’ (Table 13). Some 16.9% made use of the assistance offered by activists established in the combat zone (Syria and Iraq), and the remaining 6.8% depended upon recruitment networks in other countries. The differences between men and women shown in Table 13 reflect a somewhat higher propensity for women to be recruited online, establishing a personal contact with someone already based in these countries.
Table 13: Individuals arrested in Spain for IS-related terrorist activities (June 2013-August 2016) who had travelled to combat zones, had tried to or had the intention of doing so, by sex and according to their facilitator (%)
Network inside Spain
Activist in the conflict zone
Network in third country
Apart from the detainees who were once foreign fighters or aspired be, there has existed a small, but at least until the summer of 2016, growing number of jihadist militants in Syria and Iraq, mainly – but not exclusively – in the ranks of IS, originating from Spain (Figure 1). Towards the end of 2013 these were thought to number around 20, by mid-2014 some 50, one year later 116, and at the end of 2015 almost 140. In February 2016 it was calculated that the number of foreign fighters from Spain in Syria and Iraq was 153 and six months later this figure had risen to around 190.
Figure 1: Cumulative number of detainees in Spain for IS-related activities and the number of foreign fighters from Spain to Syria and Iraq (June 2013-August 2016)
Source: EDBJS and Spain´s Ministry of Interior.
Between November 2013 and August 2016 the number of foreign fighters that had travelled from Spain to Syria and Iraq increased approximately at a rate of five per month. In the summer of 2016 there was no indication that this trend would remit or reverse. However, latest updated figures may reflect that more individuals are being identified by the security services rather than there was a real and sustained increase of the phenomenon. It is estimated that at least 47 of them, that is to say around 25%, have lost their lives in these Syria and Iraq: seven or eight in suicide attacks and the rest in the course of armed confrontations, or as a result of the aerial strikes carried out by the international coalition against IS since September 2014.
Taken together these around 190 foreign fighters in Syria and Iraq originating from Spain (up until August 2016), consist of both Spaniards and Moroccan residents of Spain. Particularly prominent among the Spaniards are those characterised by being the young offspring of Moroccan immigrants. Some of them were born in Ceuta and Melilla, others were hailing from Catalonia and Madrid. About 10% of the foreign fighters who went from Spain to Syria and Iraq in 2013-16 were thought to be women.
In the case of Spain, the vast majority of the 130 individuals arrested between June 2013 and August 2016 for IS-related terrorist offences took part in jihadist activities with others and not as lone actors. Actually, they were typically part of cells, groups, or networks (CGN) of varying size, homogenous as well as heterogeneous ones. Inside these CGN, detainees fulfilled various tasks, occupying different positions, partly due to their social skills. More detainees belonged to new, transnationally operating and IS-linked CGN than those who were part of regenerated CGN which lacked cross-border ties, operated solely at the national level and were only inspired by IS.
Moreover, nearly all detainees who became involved with others belonged to CGN whose members were collectively engaged in radicalisation and recruitment functions. Yet they also regularly belonged to other jihadist aggregates that dispatched foreign fighters to Syria and Iraq, or that carried out fund-raising and propaganda distribution on behalf of IS. A majority of all those individuals arrested had either travelled to Syria and Iraq, had tried to travel, or intended to travel. Three out of 10 belonged to cells, groups or networks that had operational capabilities, carried out training activities on Spanish soil and were willing to carry out attacks inside the country–a fact which, in addition to the phenomenon of foreign fighters originating from Spain, reflects the highly networked and organized terrorist threat inherent to the jihadist mobilization prompted by IS.
*About the Authors:
Carola García-Calvo, Ph.D. is a Researcher in the Program on Global Terrorism at Elcano Royal Institute and an Associate Lecturer on International Terrorism at Universidad Pontificia de Comillas, both in Madrid. Fernando Reinares is the Director of the Program on Global Terrorism at the Elcano Royal Institute and a Professor of Political Science and Security Studies at the Universidad Rey Juan Carlos, also in Madrid, as well as Wilson Center Global Fellow and Adjunct Professor at Georgetown University in Washington, D.C.
This article was published in the journal Perspectives on Terrorism, Volume X, Issue 6 (December 2016).
 Factiva, a Dow Jones product, is a database drawing upon approximately 25,000 sources of information emanating from more than 200 countries in 28 languages.
 Here we wish to acknowledge the outstanding help on both data collection and database maintenance provided by Álvaro Vicente, Research Assistant of the Program on Global Terrorism at Elcano Royal Institute.
 It is not always easy to distinguish between cells, groups and networks. As we understand it for the purpose of this article, cells are smaller and tend to exhibit a greater degree of internal hierarchy and cohesiveness. Groups tend to be larger but have more blurred contours and are usually also a less formalized. Networks are more complex and overlapping aggregates, where individuals may also belong to other cells or groups.
 On this issue, see Petter Nesser, Islamist Terrorism in Europe (London: Hurst and Company, 2015), pp. 253-65.
 Thomas Hegghammer and Petter Nesser (2015), “Assessing the Islamic State commitment to attacking the West”, Perspectives on Terrorism, vol. 9, nr 4, p. 16-17; Europol, European Counter Terrorism Centre, “Lone actor attacks. Recent developments”, The Hague: Europol, 2015.
 Carola García-Calvo and Fernando Reinares (2014), “Pautas de implicación entre condenados por actividades relacionadas con el terrorismo yihadista o muertos en acto de terrorismo suicida en España (1996-2012)”, Madrid: Real Instituto Elcano, Documento de Trabajo 15/2014; URL:
 Between February 2013 and June 2014, the Islamic State (IS) was still known as the Islamic State of Iraq and Levant (ISIL).
 This circumstance came about before the al-Nusra Front was formally designated as the Syrian branch of al-Qaeda and, therefore, prior to ISIL being expelled from the global structure of al-Qaeda. See Fernando Reinares (2015), ‘Yihadismo global y amenaza terrorista: de al-Qaeda al Estado Islámico’, Madrid: Real Instituto Elcano, ARI 33/2015, ; also, Charles Lister, Profiling the Islamic State, Doha: Brookings Doha Center, Analysis Paper no. 13 (2014); URL:
 The following three paragraphs are based on the data corresponding to the period June 2013-May 2016, offered in Fernando Reinares and Carola García-Calvo, Estado Islámico en España, (Madrid: Real Instituto Elcano, 2016), pp. 61-62; URL: ; “Cellule de Cannes-Torcy : le terrorisme, affaire de potes”, 16 December 2015,
 Operation Kibera, conducted by the antiterrorism branch of the Cuerpo Nacional de Policía (CNP) in five subsequent phases, from August 2014 to September 2015. See Ministerio del Interior, Oficina de Comunicación y Relaciones Institucionales, Nota de prensa, 16 December, 2014; URL:
 Guardia Civil, Jefatura de Información, and Cuerpo Nacional de Policía, Comisaría General de Información, Diligencias Previas 02/2009, Atestado Policial 9883/2013, delivered 24 June 2013 to the National Court’s Central Investigative Court no. 2, p. 22-25; ‘La Brigada Al Andalus recaudaba fondos para la yihad en la mezquita de la M-30’, El Español, 10 April 2016; URL:
 Ministerio del Interior, Oficina de Comunicación y Relaciones Institucionales, “La Guardia Civil cree que la documentación incautada a los detenidos en Arbúcies (Girona) revelará datos relevantes sobre la financiación de DAESH desde España”, Nota de prensa, 27 July 2016;URL:
 Ministerio del Interior, Oficina de Comunicación y Relaciones Institucionales, “Los siete yihadistas detendidos por la Policía Nacional crearon una red delictiva internacional para enviar material logístico a las organizaciones terroristas Jabhat al Nusra y Daesh”, Nota de prensa, 7 February 2016, p. 3; URL:
 Audiencia Nacional, Juzgado Central de Instrucción no. 6, Auto of 15 March 2015, p. 3; “El líder de la célula yihadista evitó su arresto en España al irse a Siria”, Europa Press, 13 March 2015; URL:
 These data further corroborate a well-known argument on foreign fighting as the more frequent choice of Western-based jihadists, as advanced by Thomas Hegghammer in “Should I Stay or Should I Go? Explaining Variation in Western Jihadists’ Choice between Domestic and Foreign Fighting”, American Political Science Review, vol. 107, no. 1 (2013), pp. 1-15.
 Interview conducted by Dr García-Calvo with a senior law-enforcement officer of the Secretaría de Estado de Seguridad, Ministerio del Interior, in the second week of September 2016.