German police on Sunday arrested two Iranian brothers after receiving a tip from U.S. intelligence that the men could be plotting a chemical attack.
In an overnight raid northwest of Dortmund, police arrested the brothers, aged 32 and 25. The older brother was the primary suspect in the investigation, according to the Düsseldorf prosecutor's office, and allegedly was preparing an attack using the deadly substances cyanide and ricin.
The alleged motive for the attack was Islamic extremism, though it is unclear what the target would have been, and prosecutors did not find the toxic substances during their initial search of the apartment.
While the German prosecutor said there was no indication that the Iranian government was involved in the alleged plot, the news of the brothers' arrest comes as the regime has been implicated in several international plots, including the attempted kidnapping of journalists in the United States.
The primary suspect was living in Germany as a refugee, according to the prosecutor. His brother "was convicted previously of attempted murder," CBS News reported.
Police foiled the brothers' alleged plot five years after arresting a Tunisian man and his wife who also planned a chemical attack. The couple was found guilty of planning a ricin attack on behalf of the Islamic State.