The students are accused of gathering weapons and buying bomb-making material inside a local Home Depot. Police found shotgun shells, bullets, black powder and explosive devices inside the home of a 16-year-old student.
They also arrested a 17-year-old after they discovered rifles, shotguns and shotgun shells inside his home.
That 17-year-old attended nearby Immaculata High School.
While there was no threat against that school, investigators swept the building anyway and found no signs of explosives.
Officials say the 17-year-old is a competitive rifle shooter and the weapons found in his home were registered to his father.
After further investigation Somerset officials determined the 17-year-old provided the 16-year-old with the shotgun shells to make the homemade explosives. Officials also say, the two teens purchased PVC piping, wiring, light sockets and light bulbs from a Home Depot in Bridgewater -- and began constructing the explosives.
Prosecutor Wayne Forrest said the 17-year-old has been charged with third-degree possession of destructive devices.
Bridgewater Superintendent James Riccobono credited the vigilant action of another student for making authorities aware of the threat.
"For years, we've promoted the hope that students who have knowledge of any possible threat to the well-being of the school report that information to a school official. In this instance, this hope was materialized with a report from a member of the student body," Riccobono said.
The 16-year-old is being held at the Middlesex County Juvenile Detention Facility on numerous charges, including attempted murder and possession of explosives.