The school system's top cop and two other officers were placed on administrative leave Wednesday after the video's release.
A lawyer for the officer seen striking the teenager has said his client was responding to a report of an intruder on the grounds of Reach! Partnership School. School officials originally said they were unsure he was enrolled at the school.
In a statement Friday, the school system said it had scheduled an interview with the young man and his parents.
"The young man is believed to be a student on the school's roster," said the statement, adding that the system's internal affairs investigator as well as city police and prosecutors were reviewing the incident.
The five-second video, posted online this week, shows the uniformed officer slapping the teen three times -- one slap loud enough to hear a pop -- and then kicking him while yelling profanities. The incident happened Tuesday, school officials said.
The unidentified officer who struck the youth and a female officer standing behind him are on paid administrative leave, said Karen Parks, spokeswoman for the Baltimore public school system.
The officer is under investigation for assault and misconduct, officials said.
"As a parent of a Baltimore city school student, I was appalled by what I saw," Mayor Stephanie Rawlings-Blake said of the video earlier this week. "The behavior that was demonstrated ... is certainly something you never want to see."
Baltimore School Police Chief Marshall Goodwin was also placed on paid administrative leave, said Parks, describing the move as a "personnel matter."
Neither the officer nor the teen involved in the incident have been identified by officials, although attorneys for both are making public statements.
The day after the incident, Lauren Geisser, an attorney for the teen and his parents, said she had documentation identifying the youth as a 10th grader at the school. She said he suffered face and rib injuries.
"The boy had a right to be at the school where he was an enrolled student," she said. "With respect to refusing to leave the school, the student didn't want to leave the school where he had a right to attend."
Baltimore police and state's attorney's office are handling the criminal investigation, officials said.
"I am completely appalled and disappointed by what is depicted in the video," the school system's CEO, Gregory Thornton, said in the statement.
Akil Hamm, acting chief of the Baltimore school police, said the "excessive force" displayed in the video was "very troubling."
Michael Davey, attorney for the officer who struck the young man, said his client responded to a call of an intruder.
Davey said the online video captures only a few seconds of an encounter several minutes long.
The young man became belligerent and angry after the officer repeatedly asked him to leave, according to Davey, who said what happened earlier does not appear to have been captured on video.
Geisser said she had no information about her client's response.
"One would expect that police officers that are specifically charged with protecting children would exercise restraint, care and understanding when dealing with these children," she said. "Instead, these officers used their powers to inflict harm on a student who was trying to attend school lawfully."
Baltimore school police officers not only patrol the schools but also investigate offenses, counsel students and advise school staff on security issues, according to the district's website.
According to Maryland law, school police officers have all the powers of state peace officers and receive the same academy training as city police officers, the website said.