The deadly terror attack carried out by an Isis militant in Vienna this week that killed four people and injured 22 was the first such atrocity in Austria for a quarter of a century.
Following Islamist-inspired outrages in France and Germany, including the brutal killing of three people at a church in Nice, it has heightened fears that a new terror wave could be building across Europe.
The UK responded by raising its terror alert level to “severe” while the head of Germany’s domestic intelligence agency warned it was “highly likely” that extremists were plotting copycat attacks. Austria has sent the army to guard sensitive sites and France has more than doubled its military deployment to 7,000.
Security officials believe the resurgence of the threat is real, made more potent by the large number of European jihadis who have returned from Iraq and Syria or who sought to travel there. They have repeatedly warned about the danger from this group of extremists with proven terrorist intent.
“These attacks occurring closely one after the other raises questions about whether it is all just a coincidence,” said Raffaello Pantucci, a counterterror expert at the London-based Royal United Services Institute.
“The underlying problems which drive violent Islamist extremism have not gone away,” he continued. “There is the fundamental problem of radicalised people who joined Isis coming out of prison still radicalised.”
The Vienna attacker was one such offender. Kujtim Fejzulai was a 20-year-old Islamist extremist sentenced to 22 months in prison for attempting to travel to Syria to join Isis, but released in December after just eight months.
The Islamist extremist who killed the French teacher Samuel Paty last month had reportedly been in contact with an Isis fighter in Syria. The man suspected of stabbing a tourist to death in the German city of Dresden last month was a convicted Isis recruiter released from juvenile prison only five days earlier.
Before these attacks, jihadi terrorism across Europe appeared to be in decline. According to data from Europol, 21 Islamist terror attacks were made in 2019, down from 24 in 2018 and 33 in 2017. Isis propaganda appeared to lose momentum as its so-called caliphate in Iraq and Syria was recaptured, but recent events are reigniting the networks.
One flashpoint was the decision in September by French magazine Charlie Hebdo to republish cartoons caricaturing the Prophet Mohammed to mark a new trial relating to the deadly 2015 terror attack on its offices. The subsequent anti-French campaign whipped up on social media was a force behind the Paris and Nice attacks, the authorities believe.
Long before these cartoons were republished, however, European security agencies were alert to the risk of attacks increasing again.
An estimated 5,000 Isis supporters left Europe to fight with Isis, but managing those who have returned — and others who were caught before they could travel — is a near impossible task. Austria’s intelligence and security service warned in a report last year that, despite fewer “jihadi travellers” returning to Austria than expected, they posed a “significant danger” that was “difficult to predict”.
Rajan Basra, a terrorism expert at the International Centre for the Study of Radicalisation at King’s College, London, criticises government efforts to counter the problem. The approach until recently was to get foreign fighters “off the street, put them in prison and then leave them there,” he said.
“Very little thinking was actually given as to what should be done in terms of their release and reintegration, and what you should do in terms of monitoring after they are out [of prison],” he added.
ICSR research also showed the tendency for foreign fighters — who were likely to have been prosecuted within a short timeframe and given similar sentences — to be released around the same time, which means juggling resources between multiple potentially dangerous individuals.
Of 196 terrorists convicted in France for offences relating to Syrian travel, 45 were due for release this year, 57 in 2021 and 46 in 2022, according to an ICSR report. Sweden has reported having 47 extremists behind bars who are not on life sentences, of whom nearly half were due to be released this year.
Mr Basra said the complicated task of deradicalising terrorists must involve a joined-up approach that combined monitoring by security officials with religious mentoring and input from social workers and criminal justice experts.
However, it is also notoriously unreliable. Usman Khan, a convicted terrorist jailed for his involvement in a plot to bomb the London Stock Exchange, killed two people in central London a year ago and just 11 months after his release from prison. Khan persuaded his mentors that he was a reformed character, and carried out his attack at a rehabilitation conference he had been invited to attend.
Karl Nehammer, Austria’s interior minister, told the Kurier newspaper this week that the Vienna attacker had “massively deceived all those who acted to the best of their knowledge and conscience to achieve his early release”.
The new terror threat has been complicated by the coronavirus pandemic, which has limited travel opportunities for terrorists and dramatically restricted the types of large gatherings they typically target. Ken McCallum, head of the UK domestic intelligence agency MI5, spoke of the difficulty of conducting surveillance when town centres had been emptied of people.
The task now is to explore possible links between the recent terror incidents. “This might look like lone-wolf activity but there’s also a thread linking back to previous attacks,” one European security official said.
Mr Pantucci added that it was unclear how long the tendency to imitate other atrocities would last. “People who have intent but are wondering what to do and when . . . to strike are most likely to be inspired by seeing other attacks and copying them.
“The important question is, for how long does that copycat effect echo?”
Additional reporting by Guy Chazan in Berlin and Valerie Hopkins in Budapest