CLAREMONT, N.C. -- Extra police were on duty at Bunker Hill High school in Catawba County today following a threat to the school made yesterday on social media.

This is the same school where a video was posted on social media last week that showed one student violently punching and hitting a younger, smaller student.

Authorities would not detail the threat that was made but was able to find out who had posted it.

In a letter to parents, Bunker Hill Principal, Dr. Jeffrey Isenhour wrote, "The Sheriff's deputies contacted those who posted and found no credible evidence. We feel Bunker Hill High School is safe for all of our students."

Three students who were allegedly involved in the videotaped beating were disciplined according to the school department.

One parent blamed administrators for not stopping the fight sooner.

"Nobody stepped in. We have teachers and guardians and our schools are like prisons, so where are the people who are keeping him?" asked Valencia Griffin.

Another parent said she might not send her kids to Bunker Hill.

"Because of all that's going on there," said Jessica Hopkins.