The hor­rific bomb­ings in Brus­sels on Tuesday morning killed dozens and injured hun­dreds at the city’s air­port and a train sta­tion, leaving another Euro­pean nation reeling after a ter­rorist attack and gen­er­ating more ques­tions about the ongoing fight against terrorism.

We asked an inter­dis­ci­pli­nary group of fac­ulty mem­bers for their insights into var­ious aspects of these attacks, with a par­tic­ular focus on Brus­sels as a target, inves­ti­ga­tions into acts of ter­rorism, and com­mu­nity resiliency.

Max Abrahms, assis­tant pro­fessor of polit­ical sci­ence, and ter­rorism theorist

What’s most remark­able about the Bel­gium attacks?

What’s most remark­able is the size of the ter­rorist net­work. It’s become clear that the per­pe­tra­tors of the Brus­sels attacks were con­nected to the Paris attacks—part of a net­work of more than 35 people. That’s a huge number of people and deeply wor­ri­some. Polit­ical sci­en­tists have found that there is power in num­bers. All else equal, orga­ni­za­tions tend to gain capa­bility as the number of mem­bers grows.

Indeed, the number of fighters is com­monly used as a proxy to mea­sure mil­i­tant group capa­bility. This is a rea­son­able mea­sure because research has found a strong cor­re­la­tion between the mem­ber­ship size of a group and the amount of blood­shed it inflicts. Of course, even a lone wolf ter­rorist can inflict lots of harm. The Amer­ican lone wolf ter­rorist Tim­othy McVeigh killed 168 people in the mid-​​1990s. But a single person cannot easily sus­tain a cam­paign. Two Islamic State-​​inspired attackers man­aged to kill 14 people at a Christmas party this past December in San Bernardino, Cal­i­fornia. Can you imagine how much more damage they could have inflicted with a net­work of more than 35 people? So, I am most struck by the size of the net­work involved in the Bel­gium attacks. This is really the night­mare we wor­ried about, as large num­bers of for­eign jihadists are returning to the West not with peace on their minds.

Mai’a Cross, asso­ciate pro­fessor of polit­ical sci­ence and inter­na­tional affairs, who studies Euro­pean pol­i­tics, secu­rity policy, and crises

Why would Brus­sels be a target for a ter­rorist attack?

While Bel­gium has con­tributed more per capita to fighting Da’esh than any other Euro­pean Union country, an attack like this could have hap­pened in any number of Euro­pean cities.  More­over, there have been numerous Da’esh-inspired attacks all over the world. To the extent that the threat in Europe is some­what higher, it is largely because of its rel­a­tive prox­imity to the Middle East, its rel­a­tively open bor­ders, and the return of pos­sibly up to 5,000 jihadis who have received training in Iraq and Syria. These for­eign fighters have set up transna­tional net­works across Europe, and Brus­sels’ Molen­beek neigh­bor­hood is a par­tic­ular hotspot for these networks.

Daniel Aldrich, pro­fessor of polit­ical sci­ence, public policy, and urban affairs and co-​​director of the Secu­rity and Resilience Program

You write about the impor­tance of social cap­ital in building resilience in the wake of dis­as­ters and emer­gen­cies. How has our ability to build that resilience changed as the ISIS attacks proliferate?

Resilience to ter­rorism will not come from tighter secu­rity checks, check­points, drone cam­paigns, or the deploy­ment of spe­cial forces. Instead, resilience—the ability of indi­vid­uals and com­mu­ni­ties to resume the rhythms of daily life after a major shock—comes from the con­nec­tions we have to family, friends, neigh­bors, and colleagues.

We have great data from a number of shocks, including ter­rorist attacks, nat­ural dis­as­ters, and even nuclear cat­a­strophe, which show that people who are engaged with their com­mu­ni­ties, who interact with their neigh­bors, who par­tic­i­pate in fes­ti­vals and reli­gious events, are the ones who bounce back quickest. People who vote, who give blood, who pick up trash during local cam­paigns create sup­port sys­tems for them­selves that help them even during the worst crises. Even if ISIS attacks con­tinue to kill inno­cent civil­ians in Europe and if terror attacks con­tinue around the globe, those sources of resilience will not change.

Adam Hall, director of the Core Mass Spec­trom­etry Facility in the Col­lege of Sci­ence and an expert in forensic and ana­lyt­ical chemistry

How has forensic col­lec­tion and inves­ti­ga­tions evolved in recent years, as these attacks have become more common?

Inves­ti­ga­tions of post-​​blast events have not changed dra­mat­i­cally in recent years. How­ever, the impor­tance of social media, mobile devices, and com­puter foren­sics have become a crit­ical part of many inves­ti­ga­tions over the past sev­eral years, and valu­able infor­ma­tion can be obtained from a detailed review of these sources of information.

Ana­lyt­ical tech­nolo­gies for the detec­tion of post-​​blast residues become more sen­si­tive and dis­crim­i­nating over time, which can also be helpful to the inves­ti­ga­tion process. As more of these events occur world­wide law enforce­ment, as well as crime scene respon­ders, gain valu­able insight into the unique­ness of inves­ti­gating a post-​​blast crime scene. This is expe­ri­ence that is essen­tial to the inves­ti­ga­tion although no one hopes for these events to occur in order to gain this insight.

Knowl­edge of how the bombers fab­ri­cated a device can help to direct an inves­ti­ga­tion. How­ever, in the absence of this infor­ma­tion numerous items of interest will still be iden­ti­fied, col­lected, and pack­aged during the course of these inves­ti­ga­tions for fur­ther analysis.