Alarm bells are ringing in Germany after security officials learned more about a Tunisian's efforts to create ricin and use the deadly substance for a terrorist attack.

Not a particularly reassuring presence on German streets.

German authorities have now confirmed what many feared: The 29-year-old Tunisian man arrested last week in Cologne was creating a deadly biological weapon he intended to use for a terrorist attack somewhere in the country. Where exactly is still unknown, and is one of several issues still being scrutinized by investigators.

“There were very concrete preparations for such an act using, if you will, a biological bomb,” Holger Münch, president of Germany’s Federal Criminal Police Office, the BKA, told public broadcaster RBB. “This is a first in Germany.”

Various Islamist groups, Mr. Münch noted, have published instructions on the internet on how to make biological weapons from the deadly toxin ricin. “Obviously, this person was following these (instructions),” he said.

Sief Allah H., whose last name wasn’t revealed in line with German privacy laws, had already begun to produce ricin from castor seeds, according to Mr. Münch. The seeds and components required to build an explosive device were also found in his apartment.

Potential targets still unclear

The seeds of the castor bean plant are naturally poisonous and can be used to create ricin. The substance kills the body’s cells by preventing them from creating vital protein. It is far deadlier than cyanide, with no antidote; just a few milligrams are enough to kill a person when injected, inhaled or swallowed.

As early as World World I, the United States tested ricin as a potential weapon, mixed together with ammunition or spread as a dust, but never deployed it. The substance is still subject to global biological and chemical weapons conventions.

The BKA, the German equivalent to the US Federal Bureau of Investigation, or FBI, confirmed it had received information from a foreign security partner about a man ordering a potentially dangerous substance on the internet – 3,000 castor seeds. The Bild newspaper, citing an inside source, claims American security officials tipped off German investigators. Following the thwarted plot, Mr. Münch said he is considering whether to increase the domestic and international monitoring of biological weapons.

The BKA’s investigation of Sief Allah H. continues. “We don’t know what concrete targets he had in mind,” the BKA president said, adding it was unclear whether he had accomplices.

A father of four with a wife who converted to Islam, Sief Allah H. came to Germany in 2016. Media has reported that he has sympathies with the Islamic State, the terrorist group that has fought in the war in Syria and carried out attacks in Europe.

While Mr. Münch said officials don’t completely rule out “a big planned attack, as in Paris and Brussels,” most now believe such a strike is “less likely because Islamic State is weakened."

Currently, Germany has 770 people classified as a threat. Many of them are believed to have entered the country during the refugee influx in 2015 and 2016.

John Blau is a senior editor with Handelsblatt Global. To contact the author: [email protected]