BOSTON (CBS) – The Dr. William W. Henderson Inclusion School in Dorchester will be closed again Friday after a principal and another staff member were attacked by a student during dismissal Wednesday afternoon.

When Boston Police arrived at the school, an officer found Upper Campus Principal Patricia Lampron unconscious on the ground being tended to by staff members. She was taken to a hospital for treatment of serious injuries.

According to WBZ-TV I-Team sources, the 61-year-old principal suffered broken ribs and a head injury. She was released from the hospital Thursday and is resting comfortably at home.

Another staff member was allegedly hit as well, but the extent of those injuries isn’t known.

A 16-year-old girl was arraigned Thursday in Dorchester Juvenile Court on assault and battery charges.

According to investigators, a staff member approached the student and instructed her to leave the area of the school. The girl then allegedly grabbed Lampron’s hair and struck her in the head and face repeatedly with a closed fist.

The student was held on $5,000 bail and ordered to stay away from and have no contact with the victim, stay away from the school, submit to GPS monitoring and remain under home confinement if she is released.

The principal’s daughter, MaryKate Lampron, released this statement on behalf of the family:

Today our mother, Patricia Lampron, was violently attacked at school and seriously injured by a student. She was taken to the hospital by ambulance where she is being assessed and treated for her injuries. Anyone who knows her knows how passionate she is about this school, it’s students and the Henderson School community. Our primary concern is her health and safety. She will need time and support to recover from her injuries. We expect a full investigation into the circumstances of the assault to assure the safety of all the students, staff and teachers in the Henderson School Community. She wants everyone to know that there is NO place for violence in our schools.

Henderson K-12 Inclusion School Principal Patricia Lampron. (Family Photo)

Several students, staff and parents witnessed the attack. But some parents brought their children to school Thursday, unaware of what had happened. Staff ended up telling them that classes were canceled for the day.

“This violent behavior will not be tolerated,” Superintendent Brenda Cassellius said in a statement. “I am personally involved and am ensuring we are taking immediate and swift action.”

Cassellius said the decision to cancel school was for the utmost caution.

“This incident is disturbing and completely unacceptable,” Cassellius said. “We want to be clear: Violence of any kind is not tolerated and will not be tolerated in the Boston Public Schools.”

City Councilor Frank Baker met with teachers inside the school Thursday. “This school needs healing, needs to be supported,” Baker said. “We in the city need to come up with a way to support not just this school but all our schools.”

The Henderson K-12 School in Dorchester. (WBZ-TV)

Students in grades 2-to-12 attend the Upper Campus of the Henderson School.

School will be closed again Friday while they develop a safety plan to bring back students and staff and “stabilize” the learning environment. Cassellius says she’ll announce a safety plan by noon on Friday. “Our top priority is the health and safety of our students and we want to make sure faculty is prepared to return,” Cassellius said Thursday afternoon.

Although the school will remain closed Friday, the Boston Public Schools crisis team and other support staff will be available to students and teachers.

“Our thoughts are with Principal Lampron and the other staff member who was assaulted. We support the plan to deploy additional counseling support to the Henderson and will continue to advocate for more counseling staff across our schools on a day-to-day basis. We are in active dialogue with the Henderson School community regarding both the incident and the response,” Erik Berg, the vice president of Boston Teachers Union said in a statement Thursday.

“While this specific incident remains under investigation, it is important to affirm that educators, parents, students, administrators, and the community are in strong agreement that violence of any kind in our schools is always unacceptable.”

Acting Mayor Kim Janey said Thursday the incident is “deeply concerning.”

“We need to make to make sure students and school staff can be in school and be in school safely. It’s a disappointment and a concerning violent attack,” Janey said. “We need to continue to do everything possible to ensure we’re addressing trauma which is often the root cause of violence in our schools.”

CBSBoston.com Staff