I believe all three were naturalized, not born in this country.
Foxnews also said that a returned US Serviceman, a Muslim, was important in supplying information in the case....
Good to know. This also from FOXNews
The indictment also notes that a fourth person, referred to as "the trainer," was a U.S. citizen but was not named as a conspirator. One official told FOX News that law enforcement was tipped to the activities of these three men by this informant, who is an ex-U.S. military man who fought overseas and was living in Toledo. He is described as "a respected member of the Muslim community" who came forward and gave information to the authorities.