German public prosecutors are investigating a 29-year-old man on suspicion of preparing a “serious act of violent subversion” after police found an “unknown substance” during a raid of his apartment late on Tuesday.
“We need to wait for the forensic results,” a spokesman said, adding that they had not ruled out terrorism.
Daily newspaper Express and local daily Kölner Stadt-Anzeiger reported that police had found ricin, a substance that can be highly toxic in small amounts. Authorities have not confirmed the reports.
Police have said they arrested the suspect, a Tunisian citizen, along with his wife in the northern neighborhood of Chorweiler in Cologne, a city in the state of North-Rhine Westphalia. German news agency dpa reported that the wife is not suspected of any involvement.