Dresden, Paris, Nice and Vienna. After four terror attacks in barely a month, it's clear that, five years after the deadly attacks in Paris that killed 130 people, Islamist terror in Europe has not been defeated.

Once again, politicians are considering imposing stricter controls at the borders, promising closer cooperation with security services, and calling for tougher action against Islamist militants who are deemed a threat.

The most recent attacks highlight the particular danger posed by individual perpetrators who are part of a network of sympathizers. What are these people like? What motivates them? The current overview of Salafism in Germany's most populous state, North Rhine-Westphalia, warns: "Special attention must be paid to the considerable potential of young, violent Salafists. In recent years, young people have been targeted by jihadi  propaganda more forcefully and at a younger age, and have reacted to it more positively."

Oliver Roy, a French expert on Islamism, also sees predominantly young men "fascinated by the violence of jihad," and who claim to be better Muslims than their parents without spending years studying the Koran. In Roy's view, this is rebellious youth inscribing its revolt into an Islamist narrative — a narrative supplied by organizations such as Al-Qaida and the so-called "Islamic State" (IS).

Read more: Bataclan attack: How survivors cope with the trauma 5 years on

'Cult of death'

Speaking to DW, Roy referred to it as a "cult of death." When these young men kill, he said, "They expect to be killed… It's not so much an ideology [as] a personal trajectory. They have a goal: To go to paradise, to die as a martyr."

Frankfurt-based sociologist Felix Rossmeissl, who is part of a research project investigating the topic of jihad, prefers to describe it as a "probation dynamic." Young men and women, he said, want to prove they can fulfill expectations, and this is how they are coerced into committing acts of violence.

In his analysis, "It represents an alternative to conventional probation dynamics, which in our society are linked primarily to professional work and academic success." Rossmeissl says this is why young people who are having difficulty making the transition to adult life are particularly susceptible to jihadi propaganda.

Read more: Islamism: How terror attacks have shocked France

Limits of deradicalization

Thomas Mücke knows people like this. He works with them. Mücke, a qualified teacher and psychologist, is the managing director of the Violence Prevention Network (VPN), which works on deradicalizing violent extremists.

"We know, of course, that people who are unstable or who are currently going through a crisis can be recruited very quickly by people on the extremist scene," Mücke told DW.

When VPN employees work in prisons with people who are likely to pose a threat, with IS returnees, or with violent Islamists, their top priority is "to make it possible for these people to ask questions again, to be allowed to start thinking for themselves again," he said.

"In the Islamist scene, the way it works is that you have to obey, you have to subordinate yourself. And they lose the ability to ask questions and think for themselves."

Mücke, however, knows there are limits to what deradicalization can achieve. "We must be under no illusion that if we make a great effort in the area of security, in the area of socio-pedagogical work, there will never be an attack. There will always be attacks."

VPN's director speaks from bitter experience. One of the clients his colleagues were dealing with was the 20-year-old man who attacked two gay men with a knife in Dresden in early October, killing one of them. The social workers had met him two days before the attack, and again afterward — unaware their client had any connection with the murder.

Read more: EU weighs tighter border controls after Paris terrorism summit

Deceiving the unbelievers

In cases like this, Mimoun Berrissoun says "taqiyya," or the concealment of religious belief from unbelievers, plays a role. Berrissoun, a young man with Moroccan roots, founded the NGO "180° Wende" (180° Turn) in Cologne.

The people who work there, most of whom are volunteers, aim to prevent young men from sliding into extremism and criminality. "If, for example, there are court orders forcing a person to comply with certain measures, but inwardly they still haven't detached from the ideology, it's very hard to detach them from that scene, from that ideology," says Berrissoun.

Yet, considering the hundreds of people VPN has worked with, Thomas Mücke is convinced that, had they been left to their own devices, "the potential of those who might commit attacks would certainly be greater."

'Explosive situation' in prisons

The potential is already great. The number of known Islamist seen to pose a threat in Germany is currently at around 620. And according to an investigation by the Frankfurter Allgemeine Zeitung, there are more than 130 Islamists in German prisons. Deradicalization and prevention work is carried out in prisons, mostly by organizations like VPN. But the COVID-19 pandemic is having a huge impact on this work, says Jens Borchert, a criminologist at the Merseburg University of Applied Sciences. "Many programs for deradicalization in prison are unable to start up or run to the extent originally planned," he told DW.

Generally speaking, Borchert regards the situation in German prisons as "explosive." Fewer staff members are available for work in the institutions because of the coronavirus, and all sorts of conspiracy theories are doing the rounds.

This was confirmed to DW by employees working in the justice system. They emphasize that despite all the measures put in place in recent years, the danger of prisoners being radicalized while behind bars is still very present. Attacks are a subject of conversation among those in custody and, even if they don't explicitly condone violence when they're speaking to staff, some consider the French teacher who was beheaded by an Islamist extremist to have been partly responsible for his own fate.

'No chains of command'

What makes the situation so dangerous — and so difficult for the security services to maintain an overview — is that Islamist terrorism doesn't need an organization in the classical sense, with secret cells and hidden headquarters. Loose networks are enough, as is the potential of radicalized people, which can be tapped through propaganda, or indeed through other attacks.

VPN head Mücke cites the Vienna attack as an example. IS has claimed responsibility, but he notes: "There are absolutely no clear chains of command.

"Instead, the narratives are fed into the networks: 'Now you have to do something.' And then there are the people who take action — without anyone actually issuing an order for them to do so," said Mücke.

So ultimately, it's a battle to control these very narratives. This is why Mimoun Berrissoun, the founder of 180° Turn, is calling for a strong counter-movement within Muslim communities. He says it must ensure that there's no room for enticing Islamist recruiters. And it must not allow "young people to be secretly recruited via WhatsApp or Telegram," he says. 

"We have to reach these young people before they do."

The article was translated from German.