This research paper analyzes both the general threat landscape and the international norms, rules and decision-making procedures that impact the nexus between crime and terrorism. There are four factors that contribute to the long-term development of the threat related to the nexus between crime and terrorism: the role of personal connections, the Syrian conflict as a game changer, the criminal nature of ISIS and other jihadist groups fighting in Syria and Iraq, and the access foreign terrorist fighters in Syria and Iraq have to professional training and material. There are also four developments related to the international norms, rules and decision-making procedures that impact the nexus between crime and terrorism: returnees from Syria and Iraq, domestic returnees from prisons, issues regarding prosecution and convictions, and the organization of countermeasures.


This research paper zooms in on the main trends that influence the nexus between terrorism and crime. The nexus between crime and terrorism is a theme that has increasingly been the focus of debate, both in academic circles and in the policy and practitioner’s communities. Even though the increase of focus on this nexus seems to demonstrate that this issue is new, the contrary is true. The fact that there is overlap between criminal networks and terrorist -or extremist- networks has been established a long time ago. This overlap is neither new nor surprising. The context in which this overlap plays a role in defining the threat to our national security, is however subject to change. Therefore, this piece takes a closer look at factors that influence the nexus in the current state of affairs.

Analysis of the threat landscape

This part sketches the threat landscape when it comes to the nexus between terrorism and crime, with a special focus on the Dutch threat landscape. It discusses four important factors that contribute to the long-term development of this nexus within this landscape, being:

the role of personal connections;

the Syrian conflict as a game changer;

the criminal nature of ISIS and other jihadist groups in Syria and Iraq;

the access foreign terrorist fighters in Syria and Iraq have had to professional training, material but also to extreme violence.

As mentioned above, the increased focus on the nexus between terrorism and crime seems to imply that the overlap between the two is a relatively new phenomenon. It is not and this also holds for the Netherlands. Even though crime and terrorism are traditionally viewed as two separate phenomena, in the 1990s, the increase of transnational activities in organized crime and the fact that terrorism as a phenomenon was changing added to the blurring of the borders between criminal and political violence and led to increasing organizational and operational similarities.[1] There are many new and old examples in Europe and the Netherlands of for instance terrorism’s dependency on organized crime when it comes to their financial sustainability. One is the IRA sharing smuggling routes with Eastern European criminal networks- the latter using these routes to make money from prostitution.[2] In The Netherlands, research shows that part of the jihadi groups active in the first decade of this century did not only have criminal pasts but continued criminal activities to support the jihadist cause. A Dutch-Moroccan man, for example, who was active for a jihadist group at that time, carried out international cocaine shipments in order to support this group[3]. Nevertheless, there is a fundamental difference between criminal organizations and terrorist organizations: the former will continue to aim to escape prosecution and simply make money, whereas the latter aims at shaping or altering the political landscape. But this difference does not exclude cooperation between these networks: these organizations have a professional pragmatism that can and does override ideological differences. Furthermore, there are often personal connections between people within these networks that are strong enough to override any potential obstacle for cooperation.

The role of personal connections

The nexus between terrorism and crime then, is not solely defined by organizational choices in cooperation or opportunity by terrorist or criminal organizations. The connection between crime and terrorism is often most tangible on a personal level[4]. Operational organizations investigating people suspected of taking part in terrorist networks tend to group people on the basis of their adherence to certain groups – a suspect either ‘belongs’ to ISIS or to Al Qaeda, and an organization is either terrorist or criminal. But in practice, and particularly on the ground, pragmatism and a preference to invoke trusted contacts above group affiliations, seems to point to a different reality. On the ground in Syria there is evidence of cooperation between fighters affiliated with competing organizations, for instance fighters from Hayat Tahrir al-Sham working together with ISIS operatives[5]. People involved in planning attacks also seem to reach out to those they truly trust, for instance to family members, or to people they connected to in circumstances of hardship like detention or deprived childhood[6]. Whether the people they reach out to are, at that point, part of the same ‘group’ seems less relevant.

The same train of thought can be applied to the nexus between terrorism and crime. Many of the people who have travelled to Syria or Iraq to take part in jihadist activities where already known to the police, often for petty crime but sometimes also for more serious offences[7]. Many of these people -though certainly not all- grew up in relative deprivation. In Western countries, including the Netherlands, many of the people who left for Syria grew up in the same areas in the larger or middle-sized cities, where there was a relatively high level of crime, and involvement of youth in criminal activities[8]. Social cohesion within groups of young people in these circumstances seems strong, and bonds between them are tight. Some have spent time together in prison.

There are several cases known where people who have come to know and trust each other reach out to each other when they need assistance when preparing to commit offences. We have seen this happening when operatives have met and learned to trust each other in prison. Take for instance the case of Chérif Kouachi and Amedy Coulibaly. Kouachi and Coulibaly first met at the Fleury-Mérogis prison near Paris in 2007 and formed a friendship after spending seven months on the same wing. Eight years later they went on coordinating the January 2015 Paris attacks, killing 17 people[9]. We have also seen cases of family members who are involved in jihadist groups and scenes together, for instance in the recent case in The Netherlands where seven people were arrested who were planning an attack. Morat M, one of the arrested young man, is the half-brother of Abdelkarim el-A., who was killed in Aleppo in 2015. His other half-brother Mohammed was arrested in Germany in 2013 for trying to travel to the conflict zone and convicted in The Netherlands in 2016 for preparatory activities aimed at joining a terrorist organization[10].

The prison setting is not the only situation where, under shared duress, trusted bonds are formed. The same can happen when people grow up in shared deprived circumstances. The fact that many of the returnees from Syria or Iraq have grown up in neighborhoods where chances are high that at least some of their childhood friend have gone on to commit criminal offences, or even be part of criminal networks, increases the chance that their possible personal connections to their childhood friends will bring about connections with criminals or criminal networks. It is likely that potential terrorists will call upon these trusted and proven contacts when planning for terrorist offences, particularly when these contacts themselves are known to take part in illicit activities themselves, whether they are criminal or other.

The Syrian conflict as a game changer

There are some recent game changers at work, influencing the nexus between crime and terrorism, the most prominent one being the conflict in Syria and the fact that many Europeans, often youngsters, have travelled there with jihadist intentions, fought on the battlefield and lived under ISIS rule. People who have lived in these circumstances and who eventually make it back to Europe or The Netherlands, are potentially a serious threat to national security. They might come back tasked to commit attacks, might return with a personal intention to commit terrorist crimes, or might on return radicalize others or end up facilitating others[11]. But what are the game changers here when it comes to the nexus between terrorism and crime?

First of all, it is the sheer scale of the problem. The absolute numbers of people who have joined the conflict in Syria and Iraq from Europe, and who have become a part of terrorist organizations are large. At least five thousand European foreign terrorist fighters (FTFs) have travelled to the jihad arena in Syria and Iraq since the beginning of the conflict[12], about three hundred of them from The Netherlands[13]. Not only is it a large-scale problem, but it will confront Europe and The Netherlands with threats to the national security for years to come. With ISIS losing its territory and the demise of the so-called caliphate, it is a realistic scenario that many ISIS members and operatives will go underground, stay in the region, or travel onwards to other jihad arenas. This group will likely include part of the FTFs that travelled from Europe to ISIS territory and survived up until now and did not return to Europe. These people will still have European roots and links but will also be in possession of a dangerous skill set, and a transnational network of potentially dangerous contacts, and with links to crime[14]. They could decide to return to Europe at any given time in the future. Another risk for the future is the fact that there are many children of European FTFs still in Syria or Iraq, or in the broader region, for instance in captivity or in camps[15]. These minors, who will likely be raised within jihadist ideology if they are not somehow repatriated to Europe, could potentially form the terrorist networks of the future – networks with a transnational footprint, with links to many countries in Europe and likely with links to criminal networks. This will be pose a threat for years to come, particularly as we are talking about a new generation of children and youngsters.

The criminal nature of ISIS and other jihadist groups

The groups that harbored FTFs in Syria and Iraq are professional groups with a high degree of organization and an effective structure aimed at not only imposing their ideology on their followers but also at preparing them for an effective jihad[16]. In the case of ISIS, it is even an organization that used to have its own territory, its own so-called Islamic state. The fact that ISIS has been relatively successful in doing so -until their military defeat- signifies that the organization did not just focus on their ideological or violent agenda, but also had resources and skills to allocate in order to create its own economy, build capacity and organize governance.

Even though we tend to primarily think of suicide bombings and terrorist attacks when reflecting on ISIS’ terrorist activities, the practical day to day activities of ISIS closely resemble activities that are commonly associated with organized crime. ISIS is known to have, amongst other things, kidnapped people, traded in artefacts, smuggled weapons, committed hostile takeovers on banks, factories and other structures on the ground, committed extortion, committed serious intimidation, be involved in large scale prostitution, committed human trafficking and raids.

The image that still dominates public opinion is that of ISIS as an ideological organization, a terrorist organization with a religious signature. And of course, ISIS advocates its ideology strongly. There is a continuing debate about how Islamic, or religious, ISIS is, with a dominating train of arguments that poses that ISIS uses Islamic ideology simply to justify its own (violent and criminal) activities and agenda, creating a form of ‘pick and mix’ ideology that is neither coherent nor funded in Islamic religious discourse[17]. Notwithstanding this debate, it is a fact that ISIS’ activities are, in fact, criminal, and where often not aimed at the execution of its terrorist agenda but on the building of territory or the acquisition of wealth, and resemble those of organized crime. Being part of ISIS is, in practice, potentially not far off from being part of a criminal organization.

Discussing the nexus between terrorism and crime implies that there is a difference between the two, but in the case of ISIS it is necessary to note that the boundaries of what constitutes a terrorist organization and a criminal organization are so blurred that one could qualify ISIS both as a criminal and a terrorist organization. This raises the theoretical question whether the common distinction between criminal organizations and terrorist organizations is still on point in the current state of affairs, where ISIS dominates the treat landscape. From a more practical perspective it is not so much the discussion about boundaries between definitions that is of importance. It is more relevant that similar classification and compartmentalization are often used within the operational practice of countering either terrorism or organized crime, whereas they can sometimes be artificial when compared to reality on the ground. This could raise barriers that make it harder to effectively counter the threat posed by the overlap and blurring between crime and terrorism.

Easy access to training and material

Where it was previously not easy for people to gain access to terrorist organization, ISIS, but also other terrorist groups in the Syria/Iraq area like Al Qa’ida and its affiliates, turned out to be quite accessible for European FTFs. Seemingly working from the premise of ‘the enemy of my enemy is my friend’, these FTFs where not only taken up in the ranks of these groups but also had access to their capacity, training and weaponry[18]. These are terrorist groups that function in a civil war, fighting both a regime and a more ideological enemy: those not adhering to their ideology. The civil war setting gives these groups and their operatives access to different capacities compared to terrorist organizations in a different setting. They have access to advanced weaponry and train people in using them. They know how to deal with social media, use technical means professionally -think of drones, but also the covert use of IT-systems- and are very skilled in how to stay off the radar and avoid authorities.

FTFs who return to Europe or The Netherlands potentially had access to all these professional capacities. Some of them took part in criminal activities or even war crimes, some were trained in using RPGs or handling Kalashnikovs, others where part of ISIS’ internal intelligence organization and were trained to spot people who infiltrated their ranks, others where trained to use high tech innovations on the jihad battlefield. The wheeling and dealing within ISIS territory was such that it was allowed, even incited, to profit from the illegal, terrorist or criminal activities committed.

Their profile thus makes these FTFs of serious potential interest to criminal organizations: they can handle weapons, know how to avoid prosecution, have IT-skills and, even more importantly, they have been exposed to violence or have used violence themselves. It is also the sort of violence that matters: next to battlefield experience, FTFs may have committed direct, physical violence in close proximity of the victim, something that presupposes the ability of dehumanizing the victim and crossing a serious threshold[19]. Examples are the beheadings of people like those executed by Mohammed Emwazi, also known as Jihadi John, from the United Kingdom.

Multifactor Threat Assessment (10-year timespan)
Multifactor Threat Assessment (10-year timespan)

International regimes influencing the nexus

In this part the focus is on four developments that are influenced by international policies, norms, rules and decision-making procedures that impact the nexus between crime and terrorism:

returnees from Syria and Iraq;

domestic returnees from prisons;

issues regarding prosecution and conviction;

the organization of countermeasures.

Returnees from Syria and Iraq

In the general debate on terrorism in the recent years, there has been a strong focus on the threat posed by returnees from Syria and Iraq. Even though this threat is an important factor influencing the nexus between crime and terrorism, the focus on the returnee problem seems disproportional compared to the actual threat picture. Whereas two years ago there was talk about increasingly alarming scenarios of floods of returnees coming back to Europe and The Netherlands, recently these images have been subject to more nuance. People are indeed returning, but not in masses[20]. Still, the threat that they pose is real. National and international policy choices are a factor influencing the threat posed by returnees. Whether these choices indeed diminish the threat or increase it, for instance by long-term negative effects, is debatable. Think for instance of the Dutch example of the stripping of nationality and the taking away of passports – direct effect to keep people from travelling, but an administrative measure that is not indiscriminate as it can only be applied to people with double nationality. This can lead to feelings of stigmatization and frustration, increasing chances of radicalization. Or for example the fact that the Dutch, but also most other European governments have decided not to actively help children and women return from Syria Iraq, or from camps that they are held in. This might diffuse the possible direct threat that they potentially pose on return, but the long-term effects can intensify the threat. These children can become the jihadists networks of the future, and the debate about the ethics of this choice can lead to negative sentiments towards Western governments. Another example is the targeted killing of European FTFs in Syria[21], a contested approach that advocates describe as a measure that is sometimes proportional to counter imminent threat, but is deemed immoral and undemocratic by others.

Part of the group of predominantly young people who have travelled out to Syria and Iraq have done so motivated by the inclination to fill certain personal needs, for instance a sense of adventure or camaraderie, or a fascination with conflict or war. For these people, the ideological factor can sometimes be seen more as a legitimation of their actions, than as a motivation on its own. The fact that their adherence to jihadist ideology can then arguably be thin, conjures up the scenario of people returning to Europe and The Netherlands with an attractive profile and skill set for criminal organizations, who are not kept away from this world or way of life for ideological reasons per se. Combined with the fact that there is a general tendency in society to be hesitant to embrace returnees into society, even if they have not been or cannot be convicted of a crime, it is likely that it is easier for these returnees to find a place in the illicit economy then in the licit economy: they might end up in criminal networks. This implies that returnees from Syria and Iraq could give an impulse to these criminal networks – and increase the nexus between these networks and terrorist networks. It is imaginable that they will relatively easily make their ideology secondary to their more basic needs: they can make money by joining criminal networks, and it is likely that the underground criminal ‘scene’ will embrace them more easily than ‘upper ground’ society will.

A further note should be made about ideology. Even though on leaving ideology was not the main catalyst for travel to a jihad arena for part of the returnees, it is likely that staying in ISIS territory and thus being constantly subjected to extreme jihadist ideology has radicalized returnees further. This bring about two possibilities. Firstly, it is possible that adherence to strong jihadist ideology keeps people away from criminal networks. Rules of conduct that come with strong Islamic ideology are for some hard to combine with the milieu and manners of the criminal world. On the other hand, the form of jihadism propagated by ISIS is not known for its coherent and concise ideological consistency. Rather, it is often described as a ‘pick and mix’ of rules and codes of conduct depending on the strategy that ISIS has planned. This form of ideology then, is again more a legitimization for action, also for criminal action. This is not new or unique to ISIS: Al Qaeda has for years used its own interpretation of the Islamic narrative to legitimize, even incite crime[22]. In a similar manner, it is plausible that returnees are willing to adapt their own ideological framework in order to legitimize their desired conduct, including the desire to commit crimes. It is then just as imaginable that the jihadist framework these returnees have on return keeps them from taking part in criminal networks as it is imaginable that it can act as a stimulus to commit crimes.

Domestic returnees from prisons

While the debate regarding returnees has focused mainly on returnees from jihad arenas up until now, there is a shift towards more attention being paid to the increasing problem of ‘domestic returnees’: violent extremist offenders (VEOs) -or radicalized prisoners- returning into society from prisons. Preventing radicalization in European prisons is of growing importance in the debate[23]. Prison is a place where the nexus between crime and terrorism can -and does- become particularly visible, as it is a place where convicted criminal and radicalized inmates and/or VEOs can come in contact with each other. When they reenter society, such contacts can increase the threat posed by former detainees- and can increase occurrences of the nexus between crime and terrorism. Choices regarding the way regimes deal with the imprisonment of convicted VEOs are therefore of influence on the analysis of the nexus between crime and terrorism.

In the Netherlands, violent extremist offenders are segregated form the general prison population, placing them in separate detention units of two prisons, Vught and De Schie. This is done to keep them from radicalizing the general prison population, but also for governments to have opportunity to try to subject them to a tailor-made approach in order to try to disconnect them from their ideology and violent tendencies. In The Netherlands, terrorism related prison sentences are relatively short, limiting the time that can be spent on such programs[24]. More European countries are gravitating toward separating convicted terrorists from other inmates to prevent the radicalization of other prisoners[25]. This policy is increasingly subject to discussion, not in the least because the practice of segregation may reinforce extremist narratives and exceptionalism amongst them[26]. Still, there is no apparent inclination to move away from this existing policy and to either detain them amongst the general population or instead to isolate them. Isolation in the form of solitary confinement is not possible nor desirable for several reasons, including legal limitations safeguarded by the European Convention of Human Rights. Dispersion is not considered a desired approach, as the risk of VEOs radicalizing non-violent extremist offenders in prisons is deemed real. Furthermore, dispersion could increase the chance of new networks being formed between crime and terrorist milieus.[27]

It is to be noted that, even though general policy is focused on segregating VEOs, risks of radicalization amongst the general prison population are not excluded by this policy. This is firstly due to the fact that there are radical or even extremist individuals within the general prison population, who have not been prosecuted for terrorism related offences but are in prison for common crimes nonetheless. Adhering to extremist ideology can, and does indeed often, go hand in hand with criminal activities.

When people detained for terrorism related offences -or, for that matter, radicalized inmates- reenter society and have been in contact with regular, heavy criminals, it is more likely that they will be able to find their way into criminal networks. Contacts made in times of hardship, like in detention, tend to be contacts defined by a high level of trust. It are exactly these contacts that people who are planning to commit serious offences evoke in order to facilitate them. It is a realistic scenario that a released VEO who still adheres to for instance jihadist ideology and who plans to commit a terrorist crime, will evoke one of his contacts from prison to help him acquire weaponry or ammunition.

Prosecution and conviction

Issues regarding prosecution and conviction of suspected terrorists are also of influence on the nexus. It has been noted that, in the public debate, the so called ‘Al Capone approach’ is increasingly called for[28]. This ‘Al Capone approach’ is a consequence of the difficulties of actually convicting an individual for terrorism-related offences, leading prosecutors to convict potential VEOs for common crimes to get them off the street. Although this might generate short-term success and reduce the direct threat, there might be long-term negative effects. The ‘Al Capone approach’ can result in a situation where (suspected) VEOs are detained amongst the general prison population, allowing for contacts between extremists or terrorists and criminals, increasing the risk of the formation of new overlapping networks. Furthermore, suspected VEOs that are detained on the basis of common crimes are not necessarily subjected to tailor made rehabilitation efforts that would take violent extremist tendencies into account. A possible increase of the so-called ‘Al Capone approach’ then is another factor potentially influencing the occurrence of cross-overs between crime and terrorism in the prison setting

Recommendations agreed upon by the members of the Global Counter Terrorism Forum, state that prosecutors should aim to try suspected VEOs “in a manner duly reflecting the seriousness of the suspected crime”[29]. Still, the difficulties of building a terrorism-related case against VEOs are many, notably the lack of evidence in many cases, due to for instance issues regarding the exchange and collection of evidence. It is often difficult to maximally exchange evidence between the closed channels of intelligence and the (relatively) open channels of police and prosecution. Internationally, it has also proven to be difficult to gain access to enough evidence for successful prosecution. The optimization of ways to acquire evidence for use in the court of law when it comes to terrorist offences is increasingly subject to debate and critical improvement. Prosecutors have also gained knowledge of terrorism legislation and about the phenomena of extremism and terrorism and underlying ideologies, increasing chances on successful prosecution for terrorism related offences. Prosecutorial discretion allows prosecutors to choose their own strategy to prosecute an individual, and for what crimes, which is often informed by legal, financial and capacity considerations. Better knowledge of terrorism related laws and the ideologies behind potential VEOs actions can help them make maximally informed choices.

The above described expected development resulting from a potential increased use of the ‘Al Capone approach’ does however not completely fit with the Dutch context. In the Netherlands, persons held in the special terrorist detention units are not exclusively those that have been convicted for violent extremist or terrorist offences, but also people who are only suspected of terrorism offences. Prisoners are therefore also (controversially) sent there on the basis of their assumed violent extremism, without having been convicted for terrorist related offences. The policy of putting together VEOs and prisoners not yet convicted but suspected for terrorism related offences is controversial as they are submitted to harsh security regimes in this part of prison. This situation could arguably result in increased opportunities for contact between criminals and serious terrorists, as we know that many jihadists for instance have criminal records and contacts and being suspected does not make one a terrorist.

The organization of Countermeasures

When we presume that criminal and terrorist networks overlap, we can also state that in order to optimally counter the treat that is posed by these networks but particularly by the synergy between the two, organizations that work to counter it should be able to view it as the hybrid problem that it is. Just as it is sometimes stated that ‘it takes a network to fight a network’ when discussing interagency cooperation in countering terrorist networks, here it could be said that ‘it takes a nexus to counter a nexus’: organizations need to be able to overlook their institutional barriers between those working on crime and those working on terrorism to be effective. Unfortunately, the reality is different. Practitioners and organizations tasked with fighting crime and/or terrorism are not always able to effectively cross the boundaries between the two subjects[30].

Firstly, there are technical and legal barriers. Simply put, operational systems that carry data about criminals are often not technically compatible with systems carrying similar data for (potential) extremists or terrorists. These systems gather for instance so called ‘selectors’, meaning personal details and contact details like telephone numbers or email addresses of suspects or known offenders. While it seems a small effort to realize, it is up until now not easy to connect these systems in order to be able to cross check the data from the one database against the other, to see where the actual overlap between these networks actually is taking place. This is a technical issue – different systems, different software- but there are also legal boundaries that make it hard to connect systems designed to carry data about potential terrorists and criminals. This is particularly the case when it comes to the data coming from the intelligence organizations on the one hand and police organization on the other. Intelligence information is, by law, often classified and cannot always be exploited for use outside closed channels. This complicated cross checking the data.

Another factor that complicates synergy between organizations that work to counter crime and terrorism, is cultural. Countering crime and terrorism both require different approaches to investigations. Investigating a possible terrorist or extremist offence with the intention of preventing it, always requires investigation ‘before the fact’, whereas regular police investigations usually investigate crimes already committed, hence ‘after the fact’. Both approaches demand a different mindset from the people who work in these investigations. It is not always easy to cross over from the subject of crime fighting to preventing terrorism or vice versa, in order to take the ‘other side’ into account whilst doing one’s primary work. In other words, for an intelligence officer, it is not always evident to worry about how intelligence gathered can be used in either a police investigation or a court of law, as their concerns are focused on the intelligence investigation and prioritize direct effect on this. Similarly, it can be difficult for police investigators who focus on trying to find out who has committed a crime, to weigh in the relevance of softer signals that could possibly be of use in an investigation aimed at preventing terrorist offences. It is worth noting that both on the intelligence as on the police side, there are also capacity issues at work. Applying a synergetic approach to both policing and intelligence work requires extra man hours, hours that are often not available.

Multiyear Regime Analysis (10-year timespan)
Multiyear Regime Analysis (10-year timespan)

Conclusions and outlook

Regarding the nexus between crime and terrorism, the sketch of the threat landscape is not pretty. The nature of an organization like ISIS poses questions about whether the distinction between criminal and terrorist organizations as it is currently and commonly defined is still on point. The sketch of the activities of ISIS and its criminal and professional nature also give insight into the way a stay with this organization negatively affects FTFs that might return to Europe. They are often used to violence and are very suitable to play a role in organized crime, taking into account the skill set that they will take with them on return. The expectant difficulty they will encounter when they do try to find a place in society, due to criminalization, stigmatization and a hostile stance towards them, will likely make them seek ‘ shelter’ in underground networks, increasing chances that these FTFs might give an impulse to (organized) crime[31]. For some, ideology might be used to legitimize their criminal activities, or even incite it. In other cases, their ideological narrative is possibly rather thin and constructed enough to easily be shed when personal needs dictate to do so. Realizing that personal contacts, particularly those formed under duress, play an important role in how terrorist and criminal networks overlap, the transnational contacts these FTFs bring along with them increase the threat, but also the chance of a growing nexus between crime and terrorism.

Wrapping up the discussion on four factors influencing the nexus between crime and terrorism, we see that the conflict in Syria has potentially far reaching consequences for the development of this nexus. With FTFs returning to Europa from Syria and Iraq, there is a serious chance that the overlap between criminal and terrorist networks will grow and the threat posed by it will intensify. These FTFs that are catalyst for this growth are a serious threat: they are hardened and trained and can be potentially very harmful both in a criminal or in a terrorist milieu. This is a long-term development: FTFs can return over the course of years, and in the meantime, networks of the future with transnational links into both criminal and terrorist networks are built. The problem of ‘domestic returnees’ from prisons is another factor that could potentially increase the nexus: with possible increase of the trend of convicting suspected terrorist for lesser, common crimes to get them of the street, there might be more contact between suspected terrorists and criminals in the general prison population -contacts that can be used once detainees are back into society and recidivate. Finally, the difficulties in bridging gaps between the operational practice of countering terrorism and investigating crime are an obstacle in countering the threat posed by the overlap between criminal and terrorist networks. There is an intensifying debate on the subject, notably mostly instigated from within the counterterrorism discourse. This could indicate a lesser appreciation for the problem from the discourse on crime. Either way, actors involved in the countering of the threat posed by the nexus are still lacking a fully decompartmentalized approach: it takes a nexus to fight a nexus. A synergetic and integral approach is best suited to counter this two-sided problem.


Makarenko, T. (2004). “The Crime-Terror Continuum: Tracing the Interplay between Transnational Organised Crime and Terrorism.” in Global Crime 6:1, pp. 129-145, and Makarenko, T. (2009), “Terrorist Use of Organised Crime: operational tool or exacerbating the threat?” in F. Allum, F. Longo, D. Irrera, P. Kostakos (eds.), Defining and Defying Organised Crime: Discourse, Perceptions, and Reality, Routledge.
Byrne, E. (2010). Republicans Resurgent. Intersec, Volume 20, No. 9, pp. 10-12.
Poot, de, C.J. en Sonnenschein, A. (2011), ‘Jihadi terrorism in the Netherlands: a description based on closed criminal investigations’, WODC.
See for instance Basra, R, Neumann, P and Brunner, C. (2016) “Criminal Pasts, Terrorist Futures: European Jihadists and the New Crime-Terror Nexus”, International Centre for the Study of Radicalization and Political Violence: “What we have found is not the merging of criminals and terrorists as organizations but of their social networks, environments, or milieus.”
See for instance Stewart, S (2017), “Can the Islamic State and al Qaeda find common ground?” in Stratfor Worldview.
See Sageman, M. (2004), ‘Understanding Terror Networks’, University of Pennsylvania Press, and Bakker, E. (2006) ‘Jihadi terrorists in Europe, their characteristics and the circumstances in which they joined the jihad: an exploratory study’, Netherlands Institute of International Relations Clingendael.
See for instance Mehra, T (2016), “ Foreign Terrorist Fighters: Trends, Dynamics and Policy Responses” , International Centre for Counter-Terrorism (ICCT).
For a striking description of the neighborhood in Delft, The Netherlands, where a group of Dutch foreign terrorist fighters grew up, see Kouwenhoven, A. (5 juli 2014), “Het was niet het geloof dat ze dreef, maar afkeer: de Paradijspoortjongeren zijn in het paradijs, hun doel” in NRC.
Basra, R, Neumann, P and Brunner, C. (2016) “Criminal Pasts, Terrorist Futures: European Jihadists and the New Crime-Terror Nexus”, International Centre for the Study of Radicalization and Political Violence
See for instance Winters, B (2018), ‘ Waarom Arnhem een Jihadnest is’, De Gelderlander, 29 September 2018.
See for instance the report of the Dutch General Intelligence- and Security Service on returnees: ‘ Terugkeerders in beeld’ (2017), link
European Union Terrorism Situation and Trend Report 2018 (TESAT 2018), Europol
See Terrorist Threat Assessment for The Netherlands 48 (2018), National Coordinator for Security and Counterterrorism (NCTV): link
Tuesday Reitano et al. (2017), “Examining the Nexus Between Organised Crime and Terrorism and Its Implications for EU Programming,” International Centre for Counter-Terrorism (ICCT).
There are no general statistics available on how many European children are present in Syria and Iraq. The Dutch General Intelligence and Security Service AIVD stated in its annual report 2017 that at least 175 children from one or two Dutch FTFs parents are present in the region. See Jaarverslag 2017, Algemene Inlichtingen- en Veiligheidsdienst,
For an insight on the professional governance structure of ISIS see Al-Tamimi, A (2015), “The evolution in Islamic State administration: the documentary evidence” in Perspectives on Terrorism 9:4.
See for instance Lebovich, A. (2016), ‘How ‘religious’ are ISIS fighters? The relationship between religious literacy and religious motivation’ in Brookings: Rethinking Political Islam Series, April 2016.
See the report of the Dutch General Intelligence and Security Service about Life with ISIS: ‘Leven bij ISIS, de mythe ontrafeld’, AIVD 2016: link
See the report of the Dutch General Intelligence and Security Service about Life with ISIS: ‘Leven bij ISIS, de mythe ontrafeld’, AIVD 2016: link
European Union Terrorism Situation and Trend Report 2018 (TESAT 2018), Europol
Boutin, B. (2017) ‘Targeted Killing of European Foreign Terrorist Fighters in Syria and Iraq’, Peace Palace Library link
Joscelyn, T (2011) ‘Anwar al Awlaki: Jihadists should steal from disbelievers’, in Long War Journal, 17 January 2011.
See for instance Rushchenko, J. (2018), ‘Prison Management of Terrorism-Related Offenders: Is Separation Effective?’ In Henry Jackson Society (7 March 2018)
Wittendorp, S. and Bakker, E. (2017), ‘Inventarisatie rechtzaken tegen jihadistische buitenlandse strijders’, Universiteit Leiden, Institute of Security and Global Affairs.
Vidino, L. and Hughes, S. (2018) ‘America’s Terrorism Problem Doesn’t End with Prison—It Might Just Begin There’ in Lawfare, 17 June 2018.
Neumann, R. and Basra, R. (2018) ‘The Crime-Terror Nexus in the Netherlands’, Crime Terror Nexus.
This approach is increasingly called for, see for instance Binning, C (2017), ‘The law’s response to the link between terrorist financing and criminal activity’ in Lexology, 9 October 2017.
See ‘Abuja Recommendations on the Collection, Use and Sharing of Evidence for Purposes of Criminal Prosecution of Terrorist Suspects’, Global Counter Terrorism Forum
Neumann, R. and Basra, R. (2018) ‘The Crime-Terror Nexus in the Netherlands’, Crime Terror Nexus.
The dynamic of jihadists seeking ‘shelter’ within the criminal milieu is not a new one, see for instance Poot, de, C.J. en Sonnenschein, A. (2011), ‘Jihadi terrorism in the Netherlands: a description based on closed criminal investigations’, WODC.