The question New Orleans investigators hope to answer: will there be another attack? | New Orleans

As investigators examine the terrorist attack in New Orleans on Wednesday, they will be hoping to answer three questions: who was responsible? How was the attack executed? And why? All will be vital to answering the most pressing question of all: will there be another attack in the immediate hours or days to come?

Their first priority will have been to identify the attacker. The FBI has said it believes Shamsud-Din Jabbar, the 42-year-old who drove a pickup truck into a crowd celebrating the new year, acted alone. He hired a vehicle, procured an assault rifle, as well as body armour and ammunition. He also fabricated what appeared to be several pipe bombs containing plastic explosives, which he may have pre-positioned to target police.

It is entirely possible that the former soldier was able to put together this arsenal himself, but, even if Jabbar was a “lone actor”, others probably had some idea, at least, of his intentions. Research has shown that many potential attackers – sometimes but not always inadvertently – reveal something of their plans to close friends or family or online before acting.

Some commentators will be tempted to look at Jabbar’s personal circumstances for an explanation of his acts. But though some factors are seen as red flags, decades of research into terrorism has failed to definitively prove a clear link between specific contexts or character traits and violence. Many experts also say that such profiling is usually counter-productive.

Establishing a connection to an extremist group is usually a more productive line of investigation. This is the “X-factor” that often turns someone who is angry, alienated or otherwise vulnerable to an extremist ideology, into a terrorist, say security officials. For those who are radicalised or “self-radicalise” online, this is particularly true. It is the intervention of outside actors – especially experienced, skilful and highly committed violent ones – that can be the most important element in moving activity from the online to the real world, with sometimes lethal consequences.

Jabbar had reportedly fixed the Islamic State flag to the vehicle used in the attack, and the US president, Joe Biden, said there was further evidence the attack was inspired by IS. This is thought to be a reference to videos Jabbar posted on social media in which he swore allegiance to the organisation shortly before the attack.

IS is a shadow of the organisation that mounted the horrific wave of attacks in Europe almost a decade ago that killed hundreds of people. It no longer has the base or manpower it possessed then, and its ideas remain attractive only to a tiny minority.

Yet it has survived – which is the most important and often most difficult challenge for any such group – and has established new hubs of activity across the Sahel region and in eastern Africa. The big attack on a concert hall in Moscow last year was the work of the Afghan branch of IS, which now appears to pose the greatest threat to international targets.

Quite where the New Orleans attack might sit on a spectrum from closely directed by IS to merely inspired by the group is unclear. Precedents in the US suggest any link is likely to be ideological rather than organisational. The US has historically been more vulnerable to attacks by lone actors – or small networks – than big organised plots.

The respected Soufan Center said on Tuesday that there was a significant rise in thwarted IS-inspired attacks in the US last year, amid a broader increase in IS-related violence worldwide.

One reason for this increase may be more and better IS propaganda – and the continuing failure of authorities to stop the circulation of violent extremist material on social media. Another may be, as officials in the US and elsewhere have been warning for many months, the radicalising effects of the war in Gaza on individuals in the west and elsewhere.

There are two important takeaways from recent research that will worry investigators. One is that potential attackers are often inspired by previous tactics or behaviours. The second is that, however isolated the individual perpetrators, attacks by “lone actors” tend to cluster in time and space, meaning that more such violence is possible in the US soon.