A Tunisian man and his German wife who bought ricin and tested the lethal toxin on a hamster have been charged with plotting Islamist-motivated attacks using a biological weapon, German prosecutors said on Thursday.

The GBA Federal Prosecutor’s Office said that 30-year-old Sief Allah H. and 43-year-old Yasmin H. had acquired knowledge on how to turn ricin into a weapon and ordered 3,300 grains of the poison, which can be found in castor beans, online.

Sief Allah H. was arrested in Cologne in June and police detained Yasmin H. a month later. The couple also face charges of planning attacks using metal balls and homemade explosives as well as seeking membership of Islamic State.

Read more: Reuters