Police in Clifton, N.J., reported that they arrested five fifth grade students Wednesday after they were found to be planning to set off explosives at a nearby high school's assembly.

The students from Clifton Elementary School #11, all aged 10 and 11, were found with written plans for attacks on Clifton High School, according to the New York Daily News.

Authorities said teachers and administrators contacted the police after they found the plans on how the attack would occur while the students were on a trip to the high school.

After arriving on the scene, police confronted the students and found a device which contained vinegar and cinnamon and determined it to be non-explosive, according to NBC New York.

"It was not a prank. They had a legitimate plan," said Clifton Police spokesman Robert Bracken.

The five students, reported to be four girls and one boy, were released into their parents' custody later Wednesday, reported the Associated Press. No criminal charges have been filed against them thus far, but all of them have been suspended.

As the investigation continues, police are exploring the possibility of an outside influence that may have helped the students formulate the plan.