(New York, N.Y.) – On the anniversary of the 2018 Christmas market attack in Strasbourg, France, the leading expert on prison radicalization and Senior Advisor to the Counter Extremism Project (CEP) Ian Acheson is warning that further action is needed to prevent future terrorist attacks.

Five people were killed and another 11 were wounded when the jihadist Chérif Chekatt launched a gun and knife attack at the Christmas market. Chekatt was killed two days later in a gunfight with police. Chekatt had a lengthy criminal history, had become radicalized and had pledged allegiance to ISIS.

Acheson said that the anniversary of the tragic events in Strasbourg highlights the need for further action and continued vigilance.

“A year on, as we reflect upon what happened in Strasbourg, and as we remember the families of those affected, we need to consider what we can do to break the link between criminality and terrorism,” Acheson said.

The path which Checkatt traveled from criminality to terrorism was far from unique. In recent years, terrorist groups such as ISIS have increasingly begun to recruit those with criminal backgrounds. The skills which these individuals have learned as criminals—and the connections which they have made behind bars—can readily be employed to carry out lethal attacks such as that which occurred last year in Strasbourg.

In September,  CEP and the European Policy Centre (EPC) published a joint report, which examined the links between criminality and terrorism titled Guns and Glory: Criminality, Imprisonment, and Jihadist Extremism in Europe.

Acheson, a co-author of the report, which examined detailed case studies spanning 10 European countries, said the issue of prison radicalization needs to be addressed urgently.

“We face a serious and enduring threat from terrorist organizations in Europe. Prisons are incubators—there is a steady stream of vulnerable, often violent people coming in, many with personality disorders and mental illnesses, who feel aggrieved and alienated. To tackle this problem, we need to be as agile as those who seek to do harm,” Acheson added.

To read the report Guns and Glory: Criminality, Imprisonment, and Jihadist Extremism in Europe, please click here.