The arrest by German police of a 29-year-old Tunisian immigrant in Cologne may have foiled what Herbert Reul, the interior minister for the German state of North Rhine-Westphalia, claimed had the potential to be “the biggest terrorist-attack Europe has witnessed” (Kölnische Rundschau, June 20; Frankfurter Allgemeine, June 29). Prosecutors accuse Sief Allah Hammami of planning an attack using the poison ricin, which he had manufactured at his home.
While such an attack would constitute a new escalation in terms of the terrorism threat in Germany, there are echoes of similar plots elsewhere in Europe. With international operations becoming increasingly important for Islamic State (IS) as it contemplates its own decline, some fear that the group is planning a major headline-grabbing attack in the West, possibly one involving a biological or chemical agent.
Arrest in Cologne
Hammami was arrested at his home, a nondescript high-rise building on Osloer Street in Köln-Chorweiler, on June 13 (Bild, June 26). The subsequent search of the premises was conducted by police dressed in full protective gear and assisted by a specialist unit from the fire services and toxicological experts from the Robert Koch Institute, a German federal government agency responsible for disease control and prevention. Hammami had, it appeared, turned his home into a laboratory where he had manufactured ricin from around 1,000 castor oil beans. During the subsequent search of the flat, authorities found 84.3 milligrams of the highly poisonous substance, as well as 2,000 unused castor oil beans. Altogether, Hammami had successfully acquired 3,150 castor oil beans (Generalbundesanwalt, June 20; Tagesschau, June 20; Welt, June 20).
The authorities also secured 250 metallic balls, fishing hooks, two bottles of acetone nail polish remover and 950 grams of what was described as a mix of aluminum powder and pyrotechnic material (Welt, June 20, Generalbundesanwalt, July 24). According to the German state prosecutor’s office, Hammami—who arrived as an immigrant in Germany in 2016—had been planning to combine the deadly toxin with a bomb, although the timing of the attack and its intended target appear to be unknown (Generalbundesanwalt, August 3).
Hammami’s wife, a German convert to Islam identified in the German media only as Jasmin H, was arrested along with her husband (Bild, June 18). She was released shortly after but was then rearrested in July, being suspected of supporting Hammami’s alleged plot (Generalbundesanwalt, July 24; Generalbundesanwalt, August 3).
Preventing this planned attack came down to a successful combination of international collaboration and local police work. In May, Germany’s Internal Security Service (Bundesamnt für Verfassungsschutz, BfV) received information from a U.S. intelligence service—presumed by German media to be the CIA—that a Tunisian national who was residing in Cologne had made an online order for ricin castor beans and an electric coffee grinder (Welt, June 19). At the same time, the German security service had received a tip-off through an established public anti-terror hotline. As a result, the BfV had already identified Hammami as a threat before receiving the information supplied by U.S. officials.
The information BfV had received led the service to believe that Hammami was planning to travel abroad, either to Syria or Egypt, to join a jihadist group. Indeed, he had failed on two occasions in 2017 to travel to Syria with the alleged intention of joining IS. He attempted to get to the border via Turkey, but was picked up by Turkish authorities and sent back to Germany, where the authorities were informed of his attempts (Express, June 15; SWR, June 20). Despite this, German authorities did not regard Hammami as a potential attacker (Gefährder) or suspected IS member, only changing their assessment after they received the information about Hammami’s online purchases. Consequently, the BfV intelligence operation was handed over to the federal police (BKA) at the beginning of June who moved to arrest him (Welt, June 19; Welt, June 26).
According to German State Prosecutor Peter Frank, Hammami had been “deeply connected to the Islamist spectrum”, although no accomplices—except his wife—have been arrested in Germany. Instead, it has been reported that Hammami’s connections to the jihadist milieu date back to his time in Tunisia (SWR, June 20; NTV, June 20). After his failed attempts to travel to join IS, Hammami linked up successfully with members of the group through social media. There, he pledged allegiance to the IS leader, according to the German state prosecutors office (Generalbundesanwalt, August 3).
While a ricin attack would constitute a new escalation in terms of the terrorism threat in Germany, similar plots have been detected in Europe. In mid-May, French authorities arrested an Egyptian–born student in Paris after intercepting messages on the secure messaging platform Telegram. According to French authorities, the student possessed “instructions on how to build ricin-based poisons” (France24, May 18).
In January 2003, British authorities disrupted an alleged ricin plot led by the suspected al-Qaeda operative Kamel Bourgass. His plan, prosecutors said, was to produce a ricin-based paste that the plotters would smear in small quantities on surfaces in public places in the British capital—such as the doors of taxis, handrails on the London Underground system, and in buses. Bourgass was convicted of conspiracy to cause a public nuisance at a trial in 2005, and two others were convicted of possessing false passports, while the others accused in the plot were acquitted (BBC, April 13, 2005). In comparison to the suspected Cologne plot, the authorities confiscated “only” 22 castor oil beans, and while equipment and recipes needed to produce ricin were found, the alleged plotters had yet to weaponize the poison.
Compared to these, the suspected plot in Cologne appears to have reached a dangerously advanced stage. German State Prosecutor Frank warned that jihadists have for some time contemplated the use of biological weapons and have “in the last years distributed time and again different manuals for the manufacturing of these, including for the production of ricin from castor oil beans” (Tagesschau, June 20).
The arrests in France and Germany show the continued interest jihadists have to acquire and use biological and chemical weapons, but the BfV believes that IS has already manufactured ricin with traces of it secured in Iraq and the Iraqi-Syrian border. In Iraq, IS had access to laboratories at Mosul University and some of Saddam’s chemical weapons engineers among its membership. There the group reportedly conducted deadly tests using thallium sulphate and a nicotine agent on human subjects (The Times, May 20, 2017).
Al-Qaeda has already experimented with producing poison from nicotine, largely because of its easy availability. The Egyptian-born bomb-maker and chemist Abu Khabab al-Masri developed a procedure for extracting nicotine poison from cigarettes in the late 1990s, as witnessed by former al-Qaeda member and later MI6 spy Aimen Dean.  In 2004, a jihadist cell in the UK contemplated applying nicotine poison to the door handles of expensive cars.  In addition, IS appears to have experimented with chlorine and sulphur mustard attacks in Syria and Iraq, becoming the first non-state actor to have developed a banned chemical warfare agent and combining it with a projectile delivery system, according to the London-based IHS Conflict Monitor.
IS has encouraged the use of these unconventional weapons abroad. In a plot uncovered in 2017 in Australia, two Lebanese Australian brothers, Khaled and Mahmoud Khayat, were allegedly planning to build an “improvised chemical dispersion device” that would release highly toxic hydrogen sulphide. The plotters had allegedly received instruction from an IS controller in Syria, who had been put in touch with them by a third brother, Tarek, who was with the group (The Australian, August 5, 2017).
The Cologne plot shows some similarities with the one prevented in Australia. The German authorities allege that Hammami received instructions on how to prepare the ricin and construct the explosive device from two different individuals via social media (Generalbundesanwalt, August 3).
Europe on Edge
Although happily prevented, the alleged Cologne ricin plot appears to alter and expand the spectrum of IS tactics in Europe. IS-directed attacks, such as those in Paris in 2015 and Brussels in 2016, have been conducted using firearms and explosives, while the spate of low-tech, IS-inspired attacks seen in Europe have involved knives and vehicles used as weapons. Often these have been carried out by lone actors, have required limited preparation and often resulted in only a small number of casualties. The suspected Cologne plotter seems to fall into a category of being initially IS-inspired, but then becoming a remotely guided attacker.
Hammami’s plot demonstrates a new level of ambition and complexity. It highlights the creativity of IS jihadists, their willingness to test a wide range of asymmetric possibilities, and the desire to achieve a much higher number of casualties with such attacks. Describing the alleged Cologne plot, BfV director Hans-Georg Maaßen warned Hammami could have “wounded, if not even killed, hundreds of people” (Welt, June 26). At the same time, the Sydney, Cologne and Paris cases also underline the risk of biological and chemical weapons knowhow spreading in the jihadist milieu.
Islamic militancy is set to remain the primary terrorism threat in Europe in the coming years. As IS comes under pressure after losing the territory it held in the Middle East, the group or one of its supporters could try to launch a spectacular attack to reinforce its image as an important actor on the international jihadist scene. Such an attack could involve using biological or chemical weapons in order to make that point.
Dr. Christian Jokinen received his doctorate from the Department for Contemporary History at the University of Turku in Finland. He specializes in political violence and terrorism.
 Aimen Dean, Paul Cruickshank and Tim Lister “Nine Lives. My time as MI6’s top spy inside al-Qaeda (2018), p.103.
 Ibid, pp.304-307