The 31-year-old Tunisian who arrived in Germany in 2016 and became a postie was jailed by the Düsseldorf regional court Thursday on charges of concocting a biological weapon and preparing a serious act of violent subversion.

Federal prosecutors had told the court that Sief Allan H., whose full name was suppressed under German privacy rules, was caught in Cologne on Juni 2018 after purchasing castor beans to produce the toxic ricin.

The case against his 44-year-old wife is subject to separate proceedings. Their arrests follow a tip, reportedly from a foreign ricin cologneintelligence service.

They had also bought 250 steel bearings, said prosecutors, and were in the advanced stages of making explosive devices, which if detonated, could have killed a large number of people.

They had done so in their apartment in Cologne's densely populated precinct of Chorweiler, with their children close by.

The Tunisian had staged a test detonation in a grassed area and tested the toxin on a hamster. It survived.

After a futile bid to join IS jihadis in Syria, he had let IS backers coach him on how to assemble a bomb, said prosecutors. 

The convicted man had admitted bomb-making activities but denied having planned an attack inside Germany

Ipj/ng (dpa, AP)