BERLIN (AP) — German authorities have thwarted a plot by a Tunisian man who created the deadly toxin ricin using castor bean seeds and planned to use the poison in an Islamic extremist attack in Germany, federal prosecutors said Thursday. Sief Allah H., whose last name wasn't given in line with German privacy laws, was taken into custody Tuesday during a raid on his apartment in Cologne. The 29-year-old was formally arrested Wednesday after a judge reviewed the evidence.