Entrepreneurial elements of human smuggling rings: findings from a multiple case study

Human smuggling towards Europe has reached an unprecedented level in the last years. The past decade has seen an intensification of the demand for irregular migration services, which increased the role of smuggling rings as service providers to assist irregular migrants in evading national border controls, migration regulations and visa requirements. These criminal organizations feature an entrepreneurial, rent-seeking behaviour using methods such as corruption, deceit, violence, and threats. Literature observes a number of elements which are essential for the establishment and development of any criminal organisation (capital collection, profit maximisation, differentiation of tasks, systems to conceal criminal money flows), but their actual presence within the human smuggling rings has never been verified. Using secondary sources, this contribution aims at verifying the presence of these entrepreneurial elements in the case of human smuggling rings by using a multiple case-study analysis.


Introduction
Human smuggling 1 towards Europe has reached an unprecedented level in the last years. Migration trends, which in the past decades featured an increase in economic migration, are now subject to an intensification also in the flows of asylum seekers.
According to the most recent estimates (UNODC 2018, Europol 2016, more than 90% of the migrants coming to the EU are facilitated by smuggling rings (Koser and Kuschminder 2015;Crawley 2010). The progressive national and supranational restrictions on migration generated a demand from migrants to irregularly cross international borders with the assistance of organized smugglers (Antonopoulos and Winterdyck 2006;Scholenhardt 1999). Smuggling rings provide services to assist irregular migrants 2 in avoiding national border controls, visa requirements, and migration regulations (Siegel 2005).
Overall, the number of smuggled people from West Africa to Europe is estimated to vary between 25,000 and 84,000 per year (UNODC 2011). The turnover of criminal rings operating in the Mediterranean in the irregular migrant business is estimated between €233 and €781 million per year, making these criminal activities the second transnational crime after drug smuggling for the amount of money generated (ibid.).
Human smuggling rings feature an entrepreneurial, rent-seeking behaviour, using methods such as corruption, deceit, violence, and threats (Aronowitz 2001). These organisations operate in a market that features facilitators, intermediaries, and money managers on the supply side and migrants on the demand side (Whittle and Antonopoulos 2020; Kyle and Koslowski 2011; Salt and Stein 1997).
Literature describes a number of cross-sectional, entrepreneurial elements typical of all criminal organisations (Gottschalk and Smith 2011;Gottschalk 2010Gottschalk , 2009) without, however, providing evidence of the occurrence/presence of these elements in the case of human smuggling rings. This paper aims at verifying the presence/absence of such elements through the analyisis of multi-case evidence (Yin 2017(Yin , 2011. To this extent, two different sources of data are used: proceedings of judicial prosecutions and reports of police operations.

Theoretical background
The human smuggling market was first analysed in 1997 by Salt and Stein, but has been discussed frequently by the literature since then. 3 A first step in the debate was made through the revision of the traditional definition of "organized crime" (Bruinsma and Bernasco 2004;Paoli 2002;Chin 1999), which originally portrayed criminal groups as mafia-type hierarchical organizations, involved in several profit-making criminal activities, and headed by a leader coordinating the operatives in a rigid chain of leadership, trust and family links. Thus, according to more recent findings, human smuggling is dealt by opportunistic, smaller-scale networks, featuring a flexible structure with part-time partnerships between small smuggling businesses of horizontally integrated individuals 4 (Coen 2011;Mallia 2010;Bruinsma and Bernasco 2004;Schloenhardt 2003;Paoli 2002;Salt and Stein 1997), and including "largely independent professionals and small cliques coordinated through a network of temporary contracts" (Campana 2018;Di Nicola et al. 2017;Leman and Janssens 2015;Naim 2010;Kyle and Scarcelli 2009;Koser 2008;Pastore et al. 2006:97;Içduygu and Toktas 2002). These networks are flexible and able to "respond readily to the growth and decline of a market for a particular illicit good or service", and the availability of new strategic resources (Gottschalk 2008:5). The coordination among such networks is "often the result of a nexus of contracts and business promises rather than the result of a structured chain of command" (Pastore et al. 2006:114) More recent contributions focused also on the crucial role undertaken by social, political and family ties in human smuggling dynamics (Herman 2006). Hence, human smuggling does not take place in a "social vacuum", but interacts with the social and political environment, including the "conditions and policies that fuel it" (van de Bunt, Siegel, and Zaitch 2014;Granovetter 1985). The phenomenon of irregular migration is therefore "deeply rooted and embedded in communities where social ties and trust relationships exist as these aspects are crucial to its success" (Siegel 2019:108;Zhang 2008). Therefore, social channels facilitate cooperation among single agent and across organisation providing services to migrants (Herman 2006;Neske & Doomernik 2006;Van Liempt 2007;Van Liempt & Doomernik 2006;Zhang 2008). Furthermore, mechanisms of trust and solidarity reinforce the security of the operations, mitigating the problem of distrust and lack of regulation typical of illegal markets (Kleemans 2013;Staring 2004). Smuggling rings which can rely on broader and more diverse social networks have better access to financial resources, secure their operations, and are generally more successful (Shane 2003;Leyden, Link, and Siegel 2014).
As criminal organisations conduct part of their operations in the illegal markets, they are subject to a series of particular "constraints that limit and define their organisational structure, size and mode of operation" (Gottschalk 2010:300;Lyman and Potter 2007). Both loose networks and mafia-type organisations, for example, need social and monetary capital to finance the criminal activities or to buy stocks of drugs to be sold by local pushers in marketplaces. Other criminal networks may rely on the assistance of professionals and money transfer service providers to launder their money into the licit economy. Criminal organisations may also modify their structure by hiring part-time agents to carry out temporary tasks, to match a particular demand in the markets or to exploit a particular business opportunity. In this sense, literature describes a number of cross-sectional, entrepreneurial elements that are essential for the establishment and development of any criminal organisation (Kleemans 2013;Dean andGottschalk 2011, 4 Shaw andMangan (2015) analysed the organisation of human smuggling rings in Libya, providing evidence on the involvement of local Libyan agents which were connecting different smuggling groups in the source countries, guiding at the same time the operations across the Sahara. The authors identified a structure of "business cooperation" between Egyptian, Tunisian, and Turkish smugglers looking for new market opportunities "given by Libyan groups which were able to control maritime assets and departure points". Shaw, M. and Mangan, F. (2015), "Enforcing 'Our Law'When the State Breaks Down: The Case of Protection Economies in Libya and Their Political Consequences". Hague Journal on the Rule of Law, 7(1): 99-110. Gottschalk and Smith 2011;Gottschalk 2010Gottschalk , 2009a. However, their actual presence within the human smuggling rings has never been verified. These elements are: i) Capital collection. The collection of funds through crime, corruption, and/or licit activities 5 is the very first entrepreneurial activity of the criminal organizations (Gottschalk 2009a;Van Duyne 1996). Capitals (social and financial) are essential for the start and development of the criminal business, providing organisations with the capacity of purchasing the goods and services that are necessary for the operations. 6 Social capital is closely linked with social networks (Koser Akcapar 2010;Vertovec 2004), and is defined as "the sum of the resources, actual or virtual, that accrue to an individual or a group by virtue of possessing a durable network of more or less institutionalized relationships of mutual acquaintance and recognition" (Bourdieu and Wacquant, 1992: 119); ii) Profit maximization. Criminal organisations have become extremely adaptable in profit-maximisation strategies, and every activity can be compared to business relations aimed at maximising the profits. This includes the discovery and exploitation of new business opportunities involving new routes and customers (Moles and Terry 1997). Part of the earnings is then reinvested in the procurement of new technologies and recruitment of new personnel, and/or by further differentiating the tasks to improve the productivity. Criminal organisations use different strategies to maximise their profits. These include the extensive use of cash payments, either for purchasing new assets or to evade controls. Further strategies include: i) investments in real estate/luxury goods; ii) investments in the financial sector; iii) investments in other illegal activities (drug trafficking, firearms trafficking, etc.); iii) Differentiation of tasks. The recent expansion of illegal markets (Lengnick-Hall and Beck 2003) has significantly changed the structure of criminal organisations, by further differentiating the type of tasks carried out by their members. In this sense, harsher law enforcement actions represent a major challenge for the human smuggling rings, which are required to increase their operational efficiency and security (Morselli et al. 2007). Thus, these organisations operate in a highly volatile, dangerously competitive, and hostile environment where their members can be arrested, closed down, or even killed at any point by competitors (Ayling 2009;Lengnick-Hall and Beck 2005). 7 The smaller criminal organizations operate on an ad-hoc basis, modifying their structure according to the market dynamics, often without a clear differentiation between operations and financial management. The more structured organisations may also feature an intermediate level, composed by specialized agents with the task of connecting the core with the 5 The capitals originated from licit activities may come, for example, from "the direct or indirect control by organized crime of legal businesses". "These may be acquired throughinter aliafictitious interposition of third persons to avoid repercussions from preventive measures, such as freezing orders or assets seizures". UNICRI (2016), Organized crime and the legal economy. The Italian case.,p. 12.Available at: http://www. unicri.it/organized-crime-and-legal-economy-italian-case 6 For licit enterprises, capitals are provided by the balance of different assets such as financial credit or loans. Human smuggling rings, operating within an illegal market, need to resort to other systems for collecting money.
operative agents, which includes intelligence gatherers, security and financial service providers. The operative level includes logisticians, drivers, transporters which can be hired on a part-time basis, or sub-contracted from other criminal organizations. In the most structured organisations, these operatives are directly hired by the intermediaries, and they do not share contacts with the leaders (Ayling 2009). This enhances the resilience of the network, as it protects its core from law enforcement and investigations which may lead to the chain of command. Finally, the operatives may also be hired on an "ad-hoc" basis, according to the variations of the demand for criminal goods/services and the most profitable routes 8 ; iv) System to conceal criminal money flows. Dirty money flows represent one of the main risks for the criminal organisations, as governments and law enforcement agencies are increasing their efforts in order to discover suspicious transactions through sophisticated systems of supervision and alert. Criminal organizations may therefore resort to a wide range of financiers, money launderers, escrow holders, to transfer and clean their profits (Global Initiative Against Transnational Organized Crime 2018:11). For the security of the operations, it is essential to implement systems to conceal these flows. These strategies include: i) use of money laundering schemes such as ponzi, hawala or multiple account systems; ii) use of legal money remittance services to common beneficiaries 9 ; iii) use of repeated small cash payments in and out of the account; iv) use of shell companies or schemes to conceal beneficial ownership; v) use of cryptocurrencies and virtual asset service providers.

Method
This work aims to verify the presence/absence of entrepreneurial elements within the human smuggling rings through the analysis of multiple case studies. Multiple case analysis allows a deep understanding of a specific phenomenon grounding evidence into several empirical cases (Yin 2017(Yin , 2011Baxter and Jack 2008). For this reason, this research methodology features a higher level of accuracy if compared to single-case designs, providing at the same time more extensive and cross-compared explanations on the social dynamics that underlie human smuggling market. However, both human smuggling and organised crime are conceptually problematic phenomena, and therefore difficult to measure. Human smuggling is a transnational crime and "acts not only outside, but also against the recording and measuring procedures established by states" (Pastore et al. 2006:97).
Data collection about people consciously involved in illegal activities can be hard: statistics on criminal organisations are mainly collected at diverse times by different actors and in different ways, and are particularly difficult to obtain even in countries with sound collection systems and reliable statistical sources. This difficulty is caused by two main factors. First, data comparison is hampered by a lack of common language between the actors in the field. Second, geographical variations affect the availability of adequate information, a factor that may jeopardize meaningful international analyses (Vermeulen et al. 2010;Costantino 2016).
The "universe" of criminal organizations is equally broad and heterogeneous. Therefore, the definitional questions regarding organised crime complicate data identification and its availability for collection and analysis (UNODC 2018;Von Lampe 2015). Furthermore, the lack of accessibility to an "overall population" of smuggling rings precludes the use of probability sampling methods. Following a purposive sampling technique, the cases have been selected on the basis of the following criteria: i) transnationality; ii) geographical location; iii) ethnicity of the organisation members; iv) organisational complexity (i.e. size of the network, differentiation the tasks).
Cases have been drafted basing on two different sources of data: proceedings of judicial prosecutions and reports of the police operations. Judicial prosecutions provide very accurate evidence of the structure of criminal organisations, as the prosecutors must give evidence to the courts of the indicted activities, as well as of the links with the accused (Pastore et al. 2006). Likewise, police reports on successful enforcement operations provide further details on the human smuggling rings structure. 10 However, these sources are subject to three main limitations which require a particular caution when analysing data. The first limitation is linked to the organization of judicial archives in the EU, which is subject of great variations from one court to another. Second, the cases collected refer to criminal organisations which have been successfully prosecuted and dismantled by law enforcement agencies, excluding from the analysis the (probably more efficient) ones that go undetected. Third, police reports and judicial prosecutions are based on given legal definitions of organised crime when attempting to construct their cases. This could lead to overestimations (or underestimations) of certain facts and circumstances of a particular case. Considering the type of sampling strategy and data used, this work does not aim at generalizing the results to the overall population of smuggling rings, rather than verifying the presence of entrepreneurial elements and the economic and social conditions that make possible their existence (Strauss and Corbin 1990).
The first case study presents a smuggling ring controlled by an Ethiopian smuggler facilitating the passage of several irregular migrants from Sudan to Libya. The case describes in detail the structure of the ring, including its articulated transnational connections, the type of strategies and resources used to increase the security of the operations, and the systems to conceal the money laundered into the licit economy. The second case study describes a smuggling ring that was financed through the use of small payments. The money was transferred through money remittance services, and involved one recipient country (France) and three senders (Afghanistan, Greece, Pakistan and United Kingdom). This system was used to collect the necessary resources to finance the activities of the organisation. The case also shows the importance of chain investigations to uncover similar cases. The third case analyses a large organization facilitating irregular immigration from Turkey and the Western Balkan region into the European Union, involving around 103 criminals throughout Europe. The ring was dismantled through a joint enforcement action (Project FIMATHU -Facilitated Irregular Immigration Affecting Austria and Hungary) of several countries which paralleled their operations. The operation was one of the largest joint-enforcement actions at European level against a smuggling ring, involving around 1200 police officers.
The fourth case describes a smuggling ring which was able to avoid law enforcement by differentiating its structure to ensure the resilience of the organization against possible arrests of some of its members. The operation, codenamed "Pakoul" after a traditional hat worn in Afghanistan, was conducted against a ring which smuggled an estimated 5000 irregular immigrants over the previous 10 months. The operation involved investigators of four different countries which paralleled their operations under the coordination of Eurojust and Interpol. In the last, fifth case, a smuggling ring facilitated the entry of around 20,000 irregular immigrants into the United Kingdom from Turkey and Eastern Europe. The ring was making use of several strategies to reinvest its profits, including the use of Limited companies and multiple bank accounts to shield the transactions. The case also provided information about the fees paid by the migrants for their journey, which included costs of transportation, forged documentation, reception and accommodation upon arrival in the United Kingdom.

Summary of cases and findings
Case 1. Smuggling ring across the Lybia-Europe route 11 The Italian police dismantled a smuggling ring controlled by an Ethiopian smuggler organizing the passage of several irregular migrants from Sudan to Libya. 12 This included their crossing to Italy and the eventual continuation towards other EU countries. The investigation focused on the structure of the smuggling ring, including its articulated transnational connections. Considering the limitations of the type of data avaliable, it can safely be observed that the smuggling ring was playing an important role in the business for many years. According to the investigations, the structure of the smuggling ring included a central core, active since 2006, which was buying "packages" of migrants (mainly Eritreans) to facilitate their entry into Libya and moving them to the Italian territory, eventually to Sweden or the United Kingdom. This core 12 Libya is commonly recognized as one of the most important points of entry for the human smuggling trade from Africa to Europe, being one of the main gateways for irregular immigration into Europe. An increasing number of migrants move through the country each year, and the presence of human smuggling rings is nowadays a factual part of Libya's social and political environment. was in charge of the management of a smuggling business operating in Sudan (Khartoum), Libya (out of Tripoli), Israel, and Italy (Sicily, Rome, and Milan), as well as in other European countries.
Phone intercepts 13 allowed the identification of the core of the ring, which was composed by Sudanese, Eritrean, and Ethiopian smugglers, with a consolidated network of relationships regulated by mechanisms of trust and violence (Campana and Varese 2013;Gambetta 2011). The core was also in charge of the collection of the capitals necessary to develop the smuggling operations. According to the intercepts, the ring featured several intermediary agents with the task of providing migrants' relatives with information on the advancement of the journey. The intermediaries, well known in the local communities, were also responsible for the business transactions, which were shielded through the use of money laundering schemes such as hawala. The main task of the intermediaries was to act as a link between the core and the operative agents, which were in charge of the organisation of the land passages with cars and trucks by arranging the routes for "packages" of migrants (up to 150 persons). The intermediaries were the only contact between the operatives disseminated all over Libya and the core of the ring. 14 It often happened that smaller groups of migrants were at some point joining larger convoys managed by the criminal group when these were already on the move in Libya. 15 The smuggling ring relied on Libyan transporters which were offering their services also to other migrants on behalf of other smuggling groups. 16 This system of procurement was financed by the core of the organization and dealt with the intermediaries. 17 The pressure to quickly collect money to avoid law enforcement made the smugglers often clash with a rival group of Sudanese smugglers trying to acquire a privileged position in the market. The peak of this conflict dates back to June 2014, when the two criminal groups discussed the suspension of the smuggling operations in Sudan for a month. 18 Part of the money earned was reinvested to increase the security of the operations by bribing the officials along the way as well as to pay a fee to the armed forces who control the area along the roads throughout Libya. Finally, according to the intercepts, a number of criminal organizations operating in Lybia joined their forces and capitals, 13 Court of Palermo, judgment against I. H. Attour Abdalmenem, 2 April 2014; Court of Palermo, DDA, Order of Custody disposed by the Public Prosecutor against Mered Medhanie, 10 April 2015. 14 Migrants were often assigned a sequential number to facilitate the process of identification along the route. The migrants "were shifted from one vehicle to another several times (up to nine times according to the testimonies of the migrants) as they cross Libya". See Kirkpatrick, D. (2015). "Before Dangers at Sea, migrants face perils of a Lawless Libya", in The New York Times, 27 April, http://nyti.ms/1JL8AHM. 15 The travel of the migrants often start in Khartoum, where the service is sold as a "full package solution", "with an average price of 2400 dollars to reach the Libyan coast by car". The journey usually takes four to five days (see note 11). 16 Intermediaries and operative are also in charge, in both in Sudan and Libya, for the selection of "fixers" arranging the release of migrants eventually arrested by police or militias along the route. 17 The prices for the crossing were subjected to variations according to the kind of boat and place. For large and more modern boats, the fee was of around 800 dollars "while 2500 dollars or more can be paid on the same boat by wealthier migrants who could buy the better places". See Court of Palermo, DDA, Order of Custody disposed by the Public Prosecutor against Mered Medhanie, 10 April 2015. 18 Ibidem. and today human smuggling seems to be interlinked with other forms of smuggling and trafficking of numerous other commodities. 19 Case 2. Use of money service businesses to finance smuggling activities 20 The French police received a tip about an Afghan national, located in France, who was using money remittance services (such as Moneygram and Western Union) to receive payments from different countries (Afghanistan, Greece, Pakistan and United Kingdom). The average amount ranged from EUR 100 to EUR 300. A chain of other similar cases was discovered by an investigation of the French police, involving Afghan or Pakistani nationals who were receiving money from the same countries. The analysis of the French FIU allowed for the identification of suspect movements of money which were reported to the police. The funds were discovered to be joined in a single capital that was used for financing a smuggling ring (based in Sangatte, France). The supects were then reported to the judicial authority and found guilty for assisting the entry and stay of irregular migrants. A money collecting service business was therefore used as a system of capital collection for the human smuggling ring, involving the use of small amounts of money to avoid police detection.
Case 3. Major people smuggling criminal network dismantled: 103 suspects arrested across Europe 21 29th January 2013: 103 persons were arrested throughout Europe, suspected of being part of a large human smuggling ring facilitating irregular migration from Turkey and the Western Balkan region into the European Union. A joint action coordinated by Europol involved 10 European countries and EULEX (European Union Rule of Law Mission in Kosovo). Several people were arrested in Croatia, Czech Republic, France, Germany, Greece, Hungary, Poland, Slovakia, Switzerland, Turkey and the Kosovo region. The operation was one of the largest joint-enforcement actions at European level against a smuggling ring, involving around 1200 police officers. Searches carried out in 117 houses led to the seizure of over 176,500 EUR in cash as well as laptops, bank statements, telephones, and a semiautomatic rifle. In 2011, Austria and Hungary launched the Project FIMATHU (Facilitated Irregular Immigration Affecting Austria and Hungary) to tackle the facilitators of irregular immigration. The aim of the FIMATHU Project is to fight human smuggling rings operating via the Western Balkans and in other European countries. Since the launch of the project, over 7500 irregular migrants have been apprehended and 891 human smuggling episodes have been identified in total. These results have led to the participation of 10 new countries in the project: Bosnia and Herzegovina, Bulgaria, Croatia, Czech Republic, Germany, Poland, Romania, Serbia, Slovakia, Slovenia and Switzerland. The case above described a successful joint enforcement action of different countries paralleling their operations, narrowing in this way the possibility for a quick recovery of the criminal organization.
Case 4. France, Greece, Belgium and UK smash a people-smuggling ring during coordinated action 22 The 17 February of 2012 has seen the arrest of six people made by law enforcement agencies of France, Greece, Belgium and the United Kingdom. The operation, codenamed" Pakoul" after a traditional hat worn in Afghanistan, was the result of more than one year of international judicial and police cooperation aimed to dismantle a human smuggling ring. The investigation was carried out by the French Police (Police aux Frontières), and involved investigators from Greece, Belgium, Germany and the United Kingdom once the links with other Member States were discovered. The action started on the 14th February of 2012 at 07:00 (Central European Time), with the arrest of two suspects in France, two in Belgium, one in Greece, and one in the United Kingdom. From the following interviews, it emerged that the Greek individual was also the main organiser of the network, smuggling an estimated 5000 irregular immigrants over the previous 10 months. The smuggling ring, consisting mainly of Afghan nationals, also recruited Kurdish and Lithuanian facilitators. The fees were on average 10,000 euros and included transportation via Turkey, Greece and France to Britain, or from France via Germany to Scandinavia.
Several house searches were then conducted at the residences of the main suspects. The searches led to the suspected leader, which was arrested in Greece. Two suspects were the arrested in France, two in Belgium and one in Britain. The operation was supported by Eurojust, which set up a judicial Coordination Centre in The Hague. Furthermore, two Europol Mobile Offices were deployed in Lille and Athens to support the operations. Both Eurojust and Europol supported the analysis of the operation results to provide the best outcomes at the judicial level.
Case 5. A smuggling ring facilitating the irregular entry of migrants into the United Kingdom 23 The United Kingdom Police Force dismantled a smuggling ring that was facilitating the entry of irregular immigrants into mainland Europe. The irregular immigrants were smuggled into the United Kingdom by lorry as well as motor vehicle, train and light aircraft. The fee charged for a channel crossing ranged from GBP 3500 up to 14,500 GBP from Turkey across Europe, including the cost of transportation and forged documentation. The fee also covered the costs of reception and accommodation on arrival in the United Kingdom. According to United Kingdom Police Force estimates, around 20,000 immigrants were smuggled into the United Kingdom by this smuggling ring, which was using the following strategies of profit-maximisation to reinvest in the licit economy: the ring purchased a number of takeaway outlets, kebab shops, and a snooker hall. An umbrella of limited companies controlled on paper by family members and associates of the subjects was controlling these activities. A new limited company was occasionally created with new company officials appointed. The core businesses (kebab shop/takeaway business) continued to operate under the same premises, and the funds generated by the operation were mostly based on cash and therefore not traceable. The assets were also purchased using cash.The ring made use of multiple bank accounts to conceal the turnover so as to not draw attention to the volume of the funds proceeding from the crime. The funds were covered by several business, personal, and family/associate accounts to conceal the source. Money was regularly sent abroad to Europe and Turkey through money service businesses using the variations of names or fake identities, names of relatives, and multiple addresses. These operations also highlighted the role of intermediaries which, well rooted in the local communities, were in charge of money collection and recruitments. In 2005, 5 persons were arrested and charged in the United Kingdom for conspiracy to facilitate a breach of immigration law and ML. One year later, the subjects were sentenced to prison receiving confiscation orders for an overall amount of GBP 1,260,000. Table 1 reports the presence/absence of the entrepreneurial elements in the cases analysed. The analysis shows that in all the cases observed the human smuggling rings featured a system for capital collection. All the smuggling rings also featured a central core of members in charge of collecting the capitals and coordinating the activities of the lower levels.

Findings
In 3 of 5 cases the rings were using strategies to maximize the profits, with a system of reinvestments into the legal economy through the use of limited companies (case 5), to acquire more sophisticated means of transportation (case 1). In one case (case 1), part of the earnings were reinvested to increase the security of the operations, by bribing the officials along the way as well as to pay a fee to the armed forces who have control of the territory along roads throughout Libya, or by using money collecting service business to assist in financing the human smuggling ring (case 2). In two organisations (case 1 and 4) social relations, and in particular mechanisms of trust and violence played a crucial role in securing the operations. In case 5, the ring reinvested the proceeds of smuggling by purchasing a number of takeaway outlets, kebab shops, and a snooker hall. An umbrella of limited companies controlled on paper by family members and associates of the subjects was controlling these activities. All the cases analyzed feature at least two different structural levels (core-operatives), whilst cases 1 and 5 described the presence of intermediary agents, well known in the local communities, which connected the core with the operatives, and systems of procurement of low level operations. These intermediaries were making wide use of their social networks to recruit new operatives, as well as potential customers. Finally, case 2 and case 5 show the presence of sophisticated systems to conceal the money flows, such as the use of small amounts of money in order to avoid the controls (case 2) or money service businesses using the variations of names or fake identities, names of relatives, and multiple addresses (case 5).

Discussion
Using the detailed knowledge laid down in a multiple case study, this paper verified the presence/absence of entrepreneurial elements within the human smuggling rings, and the socio-economic conditions that underlie their development. The main findings can be summarised as follows: & Capital collection and differentiation of the tasks are elements present in all the cases analysed, carried out to enlarge the business of human smuggling rings and consequently their profits. These strategies may include the reinvestment of part of the earnings into the legal economy or the acquisition of new technologies, in order to provide more advanced services to the migrants and to secure the operations. Human smuggling rings may also feature advanced systems to shield money flows, hiding in this way their activities from law enforcement; & The analysis also found the presence of a central core typically located in a key migration hub and directed by one or several leaders, which joined their forces. This core is in charge of the management of the operations and usually involved in several types of criminal activities, including drugs, trafficking of organs, or even legal businesses such as travel agencies or transport companies; & In all the cases smuggling rings feature at least two structural levels, including cells in charge of the operations within their territory (arranging travels, purchasing vehicles, hiring and coordinating drivers). The operative level is extremely flexible, and in the most structured networks it has no contacts with the core of the enterprise but with an intermediate level, composed by agents with direct contacts with the core of the organizations and entrusted of a certain degree of discretionary power; & Social ties play a crucial role facilitating these dynamics, providing new opportunities for the smugglers, and facilitating the access to primary resources such as money, knowledge, and contacts. Recruitment, for example, was taking place within the network of criminals, allowing them to improve their knowledge of the operations and to "learn the job". Smugglers also made a wide use of their family or regional affiliation to reach potential new customers. Social skills and relationships were also used to shield the illegal activities, through the corruption of local police officers, or using trust-based systems (such as hawala) to conceal the money flows; & Smugglers have access to internal and external channels of communication, to monitor operations and/or shifting or suspending the activities. Communication seems to play also a role in ensuring the security and resilience of the smuggling operations: this required police to adopt sophisticated strategies such as simultaneous multi-country operations to dismantle the rings. Communication also facilitates cooperation among criminals, by preventing escalations of violence for controlling a particular market or facilitating the collaboration among different networks to exploit new market opportunities.
Most researchers today agree on the limitations of deterministic models trying to explain international migration, and this should be also taken into account when re-thinking the policies to fight human smuggling. This work verified the presence of entrepreneurial characteristics within human smuggling rings and the socio-economic conditions that underlie their development. Considering the methodological limitations of this analysis, which do not allow to generalize the results to the overall human smuggling scenario, the results of this research should be however taken with particular caution. The availability of reliable cross-national data on the social organization of migrant smuggling and the enforcement of immigration controls is therefore essential to conduct an in-depth comparative analysis able to support evidence-based policy making. Human smuggling is thus an "ongoing and continually developing social process" (Potter, 1994:40), and the identification of the relationships taking place within and across the criminal networks (Antonopoulos and Winterdyk 2006) requires also more ethnographic research. The need for these types of research, besides providing more reliable data, is also important to better understand the dangers of unsafe migratory paths, while protecting potential migrants from victimisation.
Authors contribution All authors contributed to the study conception and design. Material preparation, data collection and analysis were performed by Fabrizio Costantino. Section 1 ("Introduction") and 5 ("Discussion") were drafted by Andrea Di Nicola. Section 2 ("Theoretical Background"), 3 ("Method"), 4 ("Summary of cases and findings") were drafted by Fabrizio Costantino.
Funding Information Open access funding provided by Università degli Studi di Trento within the CRUI-CARE Agreement. The research did not receive any specific grant from funding agencies in the public, commercial or not-for-profit sector.

Compliance with ethical standards
Conflict of interest The authors declare that they have no conflict of interest.
Ethical approval This article does not contain any studies with human participants performed by any of the authors.
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