Abstract: Tightening security environments are encouraging jihadis to turn increasingly to the family unit for recruits. This phenomenon complicates efforts to detect, monitor, and prevent violent radicalization. Kinship recruitment, which is difficult for security agencies to observe, is facilitated by several psychological mechanisms that bind individuals together on the path to extremism. Importantly, it deters ambivalent recruits from defecting to the authorities for fear of damaging their own valued relationships. The reliance on kinship recruitment is supplemented by greater use of social media and an emphasis on recruiting Islamic converts and women, which suggests that jihadis are adjusting their mobilization patterns to avoid detection based on previous, well-known strategies for radicalization.
The Paris and San Bernardino terrorist attacks at the end of 2015 have brought into focus the threat of homegrown extremism and its linkage to transnational actors, principally the Islamic State. Each episode of mass carnage invariably raises the question of how citizens of Western countries could undertake attacks on their host societies. What explains their radicalization and leap toward violent extremism? Why do individuals residing in relatively peaceful and affluent Western societies come to embrace extremist ideologies that emanate from distant places? This bewilderment is compounded by the fact that several of the recent episodes of mass casualty terrorism involved family members participating in the attack teams. In the Boston bombings, we had the Tsarnaev brothers; in the Charlie Hebdo massacre, we had the Kouachi brothers; in the Paris attacks, we had the Abdeslam brothers; and in the San Bernardino mass shooting, we had a husband-and-wife team of Syed Rizwan Farook and Tashfeen Malik. In three of these cases, the brotherhood of arms is literal, not just figurative.
Indeed, a New America study of 474 foreign fighters from 25 Western countries found that one-third “have a familial connection to jihad, whether through relatives currently fighting in Syria or Iraq, marriage or some other link to jihadis from prior conflicts or attacks.” A German internal intelligence service report shows that 69 out of 378 German foreign fighters traveled with family members, which is a little over 18 percent. These percentages are higher than the one reported by the American scholar Marc Sageman more than a decade ago, when his sample of 172 jihadis yielded 14 percent with kinship ties.
Kinship Radicalization in Historical Perspective
Media analysts and the public often express shock when terrorists undertake violent attacks alongside their family members. It does seem puzzling that terrorists would entangle family members in their clandestine world. Given the hardships and risks associated with radical activism, one would suspect that jihadis would seek to shield their beloved family members from harm’s way. Yet, this is not always the case as jihadis are turning to their spouses and extended families for recruits, either as homegrown terrorists or as foreign fighters.
History, however, suggests that it is not at all surprising for terrorist recruiters to mobilize their own siblings and spouses for violent extremist causes. Donatella della Porta’s 1995 study of the Italian Red Brigades during the 1970s and 1980s found that 298 out of 1,214 militants “had at least one relative, usually husband or wife, brother or sister” in the movement, which is a little less than 25 percent. Two of the founders of the Red Brigades, Renato Curcio and Margherita Cagol, were husband and wife. Six of the 19 hijackers on September 11, 2001, were brothers. Abu Musab al-Zarqawi dispatched his father-in-law Yassin Jarrad to carry out a major bombing that killed the Shiite cleric Ayatollah Muhammad Bakr al-Hakim in 2003. The 2005 Amman, Jordan, hotel bombings involved an Iraqi husband-and-wife team of Ali-Hussein al-Shamari and Sajidah al-Rishawi. In that same year, Muriel Degauque traveled to Iraq with her husband, Issam Goris, both with the intent to carry out suicide attacks. She succeeded; he was foiled and killed in the process.
Cementing ties between jihadis and local communities through marriages is an old strategy rooted in tribal traditions. Some Arab Afghans married off their daughters or sisters to fellow jihadis. The Algerian Abdullah Anas married the daughter of his Palestinian mentor Abdullah Azzam. These marriages were not always calculated to produce enduring political relationships among radicals, but their effect was the same. Abu Musab al-Zarqawi married his sister off to Khaled Mustafa al-Aruri (Abu Qassam or Abu Ashraf), who was one of Zarqawi’s closest associates from 1989 to 2001. Usama bin Ladin is believed to have arranged his own marriage to Amal al-Sada, a Yemeni from a powerful tribe in the mountain town of Ibb south of Sana`a, to bolster al-Qa`ida’s recruitment in Yemen.
Tight-knit kinship and friendship ties offer opportunities for radical socialization that simultaneously satisfy psychological needs such as avoidance of cognitive dissonance, the need for maintaining meaningful relationships, and validation from valued peers. The close associations may also entrap individuals through dynamics of peer pressure, groupthink, and what terrorism expert della Porta calls affective focusing and cognitive closure. That is, kinship and friendship ties can transpose radical political commitments, and these commitments, in turn, intensify bonds of loyalty among kith and kin. Radical Islamists facing vigilant security services are turning to these psychological dynamics to unleash homegrown terrorism and recruit foreign fighters.
Mechanisms of Kinship Radicalization
Radicalization involves adopting an extremist worldview, one that is rejected by mainstream society and one that legitimizes the use of violence as a method to effect societal or political change. Radicalization usually involves grievances, ideological socialization, social networking, and enabling support structures.
Counterterrorism specialists generally presume that it is rare for individuals to migrate from a state of normalcy to violent extremism without some ideological mediation accompanied by a series of commitments to a radical cause. However, some recent cases of radicalization cast doubt on this assumption. We have seen several instances where individuals with little prior history of radicalism suddenly surface as terrorists. These include Dzhokhar Tsarnaev, one of the two brothers responsible for the Boston bombing in 2013; Mohammad Abdulazeez, the 2015 Chattanooga shooter; and Mohammad Oda Dakhlalla and Jaelyn Delshaun, the newlywed couple from Mississippi who were arrested for seeking to join the Islamic State in 2015.
Those who do make such a leap without prior activism often do so at the hand of radicalized family members or friends who transfer their radicalism onto others by virtue of having preexisting bonds of trust and personal interdependence. This peer-to-peer radicalization suggests that the search for individual motivations may not always be helpful in explaining why persons get involved with terrorism because the motivation may not reside with the individual actors themselves, but in the small extremist milieu from which they hail. One of the most robust findings in the study of political participation, social activism, gang and cult membership, right-wing and left-wing terrorism, and religious extremism is that preexisting friendship and kinship ties facilitate recruitment into these milieus.
Radicalization and recruitment are localized and highly personal tasks involving interpersonal ties, bonds of solidarity, and trust. This is especially the case in Western societies (and strong states in general) where vigilant security services are on the lookout for overt political and religious networks seeking to radicalize and recruit others for violent ends. In a highly constricted security environment, radicals must look for recruits within preexisting networks such as educational and faith-based institutions, community centers, bookstores, religious study groups, sports teams, workplaces, professional associations, social movement organizations, local charities, and prisons. As these spaces come under the watchful eyes of the authorities, radicalizers turn to an even more secure source of recruits—the family.
Preexisting networks, including the extended family, can facilitate recruitment into radical groups in several ways. First, they often link individuals who share similar beliefs or a social category, creating an immediate collective identity. It is much easier to recruit people with a shared sense of unity or identity than to struggle to forge a new one. Regular meetings between familiar faces in non-threatening settings facilitate the exchange of ideas between the radicalizer and the recruit. Political ideas are infused with emotional commitments and high degrees of deference.
Second, a group that engages in high-risk activism, including participation in violence, depends on interpersonal ties because trust and commitment are prerequisites for inviting people into the group. The adage “don’t talk to strangers” also applies in radicalization. A recent study of 119 “lone wolf” attacks in the West revealed an astonishing statistic: 64 percent of the terrorists discussed with family and friends their intention to undertake an attack. This suggests that they had high enough levels of trust to share such damaging secrets. Recruiters first dip into the pool of family, friends, and likeminded activists because trust is already established and the risk of talking to the “wrong people” is minimized. Moreover, potential recruits are more willing to entertain radical ideas when they have shared experiences and bonds of kinship and friendship with their interlocutors. Narrative fidelity is enhanced by actual brotherly fidelity.
Third, tight-knit groups, of which families are one, present radicalizing agents with the possibility of “bloc recruitment.” The latter involves group commitments that are self-reinforcing. Once a few individuals make a commitment to a cause, it is difficult for those around them to stay behind. Bloc recruitment may be facilitated by a number of psychological mechanisms, including peer pressure, concern for reputation, groupthink, a desire to maintain extant friendships or spousal relations, or guilt feelings for staying behind.
Lastly, radicalization involves a continuous effort by recruiters to deepen the commitment of their acolytes, discourage them from heeding countervailing influences, and incentivize them to engage in acts of bridge burning (for example, leaving for training camps abroad, or declaring in front of a camera one’s intention to engage in a suicide attack). Extreme interdependency of family members minimizes resistance to these processes while it maximizes cohesion with limited transaction costs. Under such circumstances, the unit of the group becomes bound to shared ideals and heightened emotional camaraderie. Defection from the group entails a double betrayal—betraying the cause and betraying one’s family.
Implications for Counter-Radicalization
It is notable that the mastermind of the Paris attacks, Abdelhamid Abaaoud, recruited his younger brother Younes to join him in Syria when he was just 13 years old. Abdelhamid apparently also used his female cousin, Hasna Aitboulahcen, to help him secure the Saint-Denis apartment in which they both died during a police raid following the Paris attacks.
These concerning developments suggest that the fight against homegrown radicalization will become even more complicated as the ties that bind family members under normal circumstances are exploited for nefarious ends by violent extremists. Kinship radicalization seems to be part of a mix of other recruitment strategies, including expanding the proportion of converts to Islam and women in the ranks of radicals as well as increasing reliance on social media. In other words, extremists are going beyond the traditional profile of Muslim males from diaspora communities recruited through the known vectors of radicalization: mosques, prisons, and established militant milieus. The home and extended family is not entirely a new vector of radicalization, but it is becoming more prominent as security agencies are constricting the recruitment environment around radical Islamists.
Another important implication of kinship radicalization is conceptual. As noted earlier, the search for individual motivations for joining the jihad may be missing the point. Kinship recruitment suggests that radicalization is a small-group phenomenon whereby valued peers with extremist ideas transpose their extremism onto apolitical individuals within their orbit through social and psychological mechanisms that are devoid of grievances, ideology, or politics, but instead associated with love, trust, and life-long bonding.
Lastly, it is not entirely clear how counter-radicalization specialists can combat kinship recruitment given its near invisibility to outsiders prior to major acts of terrorism. Therefore, short of specific intelligence on individuals actively engaging in peer-to-peer radicalization, governments may need to design a number of incentives to encourage families to report troubling signs of in-home radicalization and recruitment without fear of prosecution or stigmatization. Such incentives may include the possibility of extending social support to help family members before they have voyaged too far on the arc of radicalization.
Mohammed M. Hafez, Ph.D., is an associate professor in the Department of National Security Affairs at the Naval Postgraduate School in Monterey, California. A specialist in Islamist violence, he is currently working on a book that explains micro-level mechanisms of radicalization among foreign fighters and homegrown extremists.
 Peter Bergen, Courtney Schuster, and David Sterman, “ISIS in the West: The New Faces of Extremism,” New America, November 2015, p. 3.
 No stated author, “Analyse der den deutschen Sicherheitsbehörden vorliegenden Informationen über die Radikalisierungshintergründe und -verläufe der Personen, die aus islamistischer Motivation aus Deutschland in Richtung Syrien ausgereist sind” [“Analysis of the information available to German security authorities about the radicalization background and process of persons who have traveled towards Syria under Islamist motivations”], Bundesamt für Verfassungsschutz [German Federal Office for the Protection of the Constitution], December 2014, p. 20.
 Marc Sageman, Understanding Terror Networks (Philadelphia, PA: University of Pennsylvania Press, 2004), p. 112.
 Donatella della Porta, “Left-Wing Terrorism in Italy,” in Martha Crenshaw ed., Terrorism in Context (University Park, PA: Pennsylvania State University Press, 1995), p. 139.
 Alessandro Orsini, Anatomy of the Red Brigades: The Religious Mind-set of Modern Terrorists (Ithaca, NY: Cornell University Press, 2011).
 The 9/11 Commission Report. National Commission on Terrorist Attacks Upon the United States. 2004.
 Mohammed M. Hafez, “The Origins of Sectarian Terrorism in Iraq,” in Bruce Hoffman and Fernando Reinares eds., The Evolution of the Global Terrorist Threat: From 9/11 to Osama Bin Laden’s Death (New York: Columbia University Press, 2014), p. 438.
 Mohammed M. Hafez, Suicide Bombers in Iraq: The Strategy and Ideology of Martyrdom (Washington, D.C.: United States Institute of Peace, 2007), pp. 167-168.
 Lawrence Wright, The Looming Tower: Al-Qaeda and The Road to 9/11 (New York, Knopf, 2006), p. 338
 Donatella della Porta, Clandestine Political Violence (New York: Cambridge University Press, 2013), pp. 243-52.
 Mohammed M. Hafez and Creighton Mullins, “The Radicalization Puzzle: Approaches to Homegrown Extremism,” Studies in Conflict and Terrorism 38:11 (November 2015).
 John Horgan, “From Profiles to Pathways and Roots to Routes: Perspectives from Psychology on Radicalization into Terrorism,” Annals of the American Academy of Political and Social Science 618 (2008), pp. 80–94.
 A recent report on foreign fighters from the United States offers several examples of individual metamorphoses into ISIS supporters in a relatively short timespan. See Lorenzo Vidino and Seamus Hughes, ISIS in America: From Retweets to Raqqa, The George Washington University Program on Extremism, December 2015. For examples from Europe, see Jason Burke, “’Jihad by family’: Why are terrorist cells often made up of brothers?” Guardian, November 17, 2015.
 John Lofland, Doomsday Cult: A Study of Conversion, Proselytization and Maintenance of Faith (Prentice Hall, 1966); Rodney Stark and William Sims Bainbridge, “Networks of Faith: Interpersonal Bonds and Recruitment to Cults and Sects,” American Journal of Sociology 85:6 (1980), pp. 1376-1395; Catherine H. Conly, Patricia Kelly, Paul Mahanna, and Lynn Warner, Street Gangs: Current Knowledge and Strategies (Washington, D.C.: National Institute of Justice, 1993); Valdis E. Krebs, “Mapping Networks of Terrorist Cells,” Connections 24, 3 (2002), pp. 43-52. Sageman, Understanding Terror Networks; Andrew V. Papachristos, David M. Hureau, and Anthony A. Braga, “The Corner and the Crew: The Influence of Geography and Social Networks on Gang Violence,” American Sociological Review 78, 3 (2013), pp. 417-447; and Sean F. Everton, “Social Networks and Religious Violence,” Review of Religious Research 57:3 (2015), pp. 1-27.
 Paul Gill, John Horgan, and Paige Deckert, “Bombing Alone: Tracing the Motivations and Antecedent Behaviors of Lone-Actor Terrorists,” Journal of Forensic Sciences 59:2 (2014), pp. 425-435.
 David A. Graham, “The Mysterious Life and Death of Abdelhamid Abaaoud,” Atlantic, November 19, 2015.
 Alissa J. Rubin, “New Suspect in Paris Attacks is Detained, Belgian Officials Say,” New York Times, January 22, 2016.