Police are investigating the details surrounding a video posted online showing students at Wilmington (Mass.) High School carrying and dragging another student through a boys' restroom and forcing the victim's head into a toilet early last week, WBZ-TV reported.

The clip shows students laughing as the deed is carried out, and officials said no one intervened, the station said.

What are the details?

Glenn Brand, superintendent of Wilmington Public Schools, sent a letter to parents notifying them of the incident, saying it happened Tuesday and “that some of our students recorded the altercation and posted this online," WBZ reported.

The station said Brand didn't say what happened in the restroom or how many students were involved, but WBZ said it obtained the video showing a student’s head being forced into a toilet.

“As a parent, let alone an educator, I am appalled that some of our students decided to act the way that they did," Brand added in a statement to the station Friday. "But what is equally disturbing is the fact that other students were present and did nothing to stop the incident, and in fact recorded the altercation. I assure you that all students who are found culpable will be held fully accountable and appropriate disciplinary and legal action will be taken.”

Wilmington Police Chief Joseph Desmond is working with the district attorney to determine charges, WBZ said, adding that the superintendent is looking into potential disciplinary action for all identified students.

Brand also told parents in his letter that “this incident comes in the wake of a number of other concerns recently involving troubling student behavior" at the high school, although he didn't elaborate, the station said. Wilmington is a little over 30 minutes north of Boston.

Desmond added to WFTX-TV that police have at least three recordings and are working with the school to identify everyone involved.

“It clearly looks like an assault as far as where I come from,” he told WFTX.

Police also are looking to see if this incident rises to the level of a hate crime or civil rights violation, the station said.

What did parents have to say?

As you might expect, parents are not happy.

“It’s horrific, just horrific,” parent Karen Walsh told WBZ. “I think we ... need to do a better job teaching our kids that bystanding is just as much as being a participant."

Parent Kyle Banks added to the station that it was "most disturbing" that "other kids did not step in to help a fellow student."

Brand said the administration will hold mandatory “bystander training” for all students and hold a series of community conversations for students, parents, and staff.