A video that captured the incident shows teacher Mark Black, who is also the wrestling coach, pinning a student to the ground. Students said he was trying to confiscate something drug-related from a student when the incident occurred.
On Friday, police arrested an 18-year-old man on suspicion of threatening a school official, battery against a school employee and possession of a weapon and marijuana on campus. He is being held on $20,000 bail.
A 16-year-old student was also arrested on suspicion of battery against a school employee. He was issued a citation and released to his parents.
Black was placed on leave while the district conducts an investigation.
Students and parents have rallied behind Black. A Facebook page supporting the teacher had more than 12,700 likes as of Monday night.
Santa Monica-Malibu Unified School District Superintendent Sandra Lyon has come under fire from parents for initially saying the kind of physical restraint used by the teacher was unacceptable.
"I want to stress that teachers are at times confronted with difficult, even threatening, situations, and they must make judgment calls to protect safety," Lyon told ABC7 Eyewitness News.
She added that placing a teacher involved in an incident on leave is standard policy for the district.
"It in no way prejudices the outcome of the investigation," she said.