Four high school students were arrested and charged Monday, after making terroristic threats against their school on Facebook, police said.

According to investigators, the teens - all students at Belleville High School - talked about blowing up or setting fire to the school on the social media website. The alleged threats were found by a fellow student who immediately alerted school officials.

The school was evacuated around 11:30 a.m. and students were sent home by Superintendent Deborah Perri, after police were notified, authorities said.

A search of the school conducted by the Essex County Sherriff's Office Bomb Squad turned up nothing unusual.

Of the students arrested were two 16-year-old females, one 17-year-old female and a 17-year-old male. The suspects were not identified because of their ages, police said.

All four students are being charged with causing a false public alarm, making terroristic threats and conspiracy.