The student, who was not identified because he is a minor, is said to have committed the act before Christmas vacation, according to the Connecticut Post.
The student from Ansonia, Connecticut is now being educated separately in a Board of Education annex building.
Ansonia Police said that their investigation is complete and that it was referred to Homeland Security, per protocol, and that the feds were conducting a probe.
ISIS is the term often used for the Islamic State terrorist group also known as ISIL.
According to the meeting minutes, the boy's mother said her son "did not breach any of the codes of conduct, he did not misbehave; the thing that he was alleged was not even founded. It was not true."
Ansonia Board of Education Vice President Carmen Pitney disagreed with the mother, saying the claims were "verified by other students and this is why the principal and the officer had to take action".