A former teacher and his twin brother have been arrested in New York charged with attempting to build a bomb.
The pair are accused of stockpiling materials for making bombs at their Bronx apartment.
Authorities have said the teachers paid High School students $50-an-hour to strip gunpowder from fireworks.
Christian Toro, the former teacher, and his brother Tyler Toro, both 27 have been charged with attempting to build an explosive device following an FBI investigation.
In the apartment, investigators found diary notes referring to an “Operation Flash” and a backpack with an index card reading, “Under the full moon the small ones will know terror.”
The diary with Tyler Toro’s name on it included a line saying, “We are twin Toros strike us now, we will return with nano thermite.”
Christian Toro was a teacher at a high school in Manhattan’s Harlem neighbourhood before resigning last year.
When his brother returned a staff computer to the school, it was found to contain a document providing instructions for building explosive devices.
The teacher told authorities he had found the document while researching the 2013 Boston Marathon bombing and had never read it or built a bomb, according to the complaint.
A search of the brothers’ apartment on Thursday found potassium nitrate, black powder identified as an explosive material, metal spheres and other potential bomb components, according to the criminal complaint.
The brothers appeared in court in New York on Thursday afternoon and were remanded in custody.
Both brothers have pleaded not guilty to the unlawful manufacture of a destructive device.
Christian Toro denies distributing explosive materials to a minor.