Two teenagers have been charged with aggravated assault, conspiracy, recklessly endangering another person, and related offenses after allegedly hitting a school principal in the face with a brick last week when he tried to break up a schoolyard fight, police said.

One of the two 15-year-old boys facing charges in that case is also under investigation in the unprovoked assault of Mark Smith, a 38-year-old man with an intellectual disability whose beating by juveniles was captured in a video that went viral Monday, a police spokeswoman said. The second 15-year-old charged in the assault on the principal is the brother of another suspect in the assault on Smith and may have been present for that assault as well, according to police.

Charges have not yet been filed against the juveniles who watched or participated in Smith's assault, but the investigation remains ongoing, police said.

Authorities are not releasing the names of the suspects involved in any of the incidents because they are juveniles.

The two assaults happened two days and three blocks apart from each other in Germantown.

The video of the assault against Smith depicts four youths. According to police, it  happened around 3 p.m. May 29 on Chelten Avenue near Knox Street. The boys engaged Smith, who works as a customer service attendant at the Cheltenham ShopRite, in conversation when "for no apparent reason" one of the youths, a 12-year-old boy, punched Smith in his face when he was not looking, police said in a news release. A 15-year-old punched him a second time, and a 13-year-old laughed at the assault in the video, which was recorded by a fifth youth, a 15-year-old, police said. A police spokeswoman said she did not know the status of the fourth youth.

Smith was not seriously injured in the incident, police said.

After the video went viral on Facebook Monday, police received information from the Philadelphia School District and the 39th Police District in Nicetown on Tuesday about the identity of the suspects. Three of the juvenile suspects, who attend a nearby Mastery Charter School, were transported with their parents for questioning to Northwest Detectives Division. A fourth suspect was identified by a 25th District officer when he saw the assault on a local television station, police said. That suspect was picked up and also transported to Northwest Detectives.

When one of the 15-year-olds allegedly involved in Smith's assault was being interviewed by police Tuesday, he told them of his involvement in the assault on Fitler Academics Plus School principal Anthious Boone, police said.

The assault on Boone, 39, happened around 2:45 p.m. May 31 outside of the school on the 100 block of West Seymour Street, police said. Boone went to intercede in fights that students from a nearby Mastery Charter School were picking with kids from his school and was punched by a Mastery Charter student, police said. Boone began filming the fighting and while he was recording, he was hit in the face with a brick by a Mastery Charter student, police said. He required stitches to his left eye.