A Central High School student allegedly choked a science teacher until he passed out, then slammed him to the floor during a fight in the lunchroom Friday.

The boy’s younger brother then punched an assistant principal who stepped in to help the teacher, St. Paul police say.

According to a police report and police spokesman Steve Linders:

The teacher was breaking up a fight around 10:30 a.m. Friday when a 16-year-old student slammed him against the wall, injuring his face and breaking his glasses. The boy then lifted the teacher off the ground in a stranglehold and slammed him onto a lunch table, a chair and the floor.

“Teacher stated he blacked out losing consciousness during the strangulation,” the report reads.

An assistant principal was trying to pull the student off the teacher when the boy’s 15-year-old brother yelled profanities at him and punched him several times in the chest.

Police arrived and arrested the two boys without incident.

Ramsey County prosecutors charged the 15-year-old Monday with fourth-degree assault and obstructing legal process.

Prosecutors could make a charging decision Tuesday about the 16-year-old.

Principal Mary Mackbee wrote in a letter to Central parents Friday, saying one of her employees was taken to a hospital for treatment.

“I will not tolerate any behavior that puts our school, students or staff at risk,” Mackbee wrote. “There are severe consequences for students who behave this way and we will follow our strict discipline procedures as outlined in the Student Rights and Responsibilities Handbook.”

The handbook classifies a crime against a staff member as either a Level 4 or 5 offense. Level 4 offenses require an out-of-school suspension of at least one day, while Level 5 offenses call for expulsion. It’s extremely rare for St. Paul Public Schools to expel a student.

Toya Stewart Downey, a spokeswoman for St. Paul Public Schools, said the teacher and assistant principal were not at school Monday.

The school district’s human resources office advises employees to try to use nonviolent holds to break up fights among students, “but if another student or staff are in harm’s way, they can intervene in the fastest and safest way possible,” Stewart Downey said.

At least one high school gives its employees whistles to call for help instead of intervening, but Central does not.

Josh Verges can be reached at jverges@pioneerpress.com or 651-228-2171. Follow him at twitter.com/ua14.

Mara H. Gottfried can be reached at mgottfried@pioneerpress.com or 651-228-5262. Follow her at twitter.com/MaraGottfried.