After a high school graduation in Daly City, a fight on campus escalated into a stabbing that left a 21-year-old injured and a 15-year-old in custody; law enforcement responded, footage circulated, and the school said it is cooperating with investigators as the community reels from what happened at Westmoor High School.
Officers were called to the campus at about 4:30 p.m. after reports of an active fight involving multiple people, and first responders found a 21-year-old suffering from stab wounds that were not considered life threatening. The injured person was taken to a hospital for treatment, and officers recovered the weapon used in the incident while securing the scene. No other injuries were reported, and the atmosphere at the ceremony quickly shifted from celebration to concern.
Police identified and arrested a 15-year-old boy at the scene, and he was booked on a charge of assault with a deadly weapon. Officials have not provided a detailed description of the weapon in public statements, and they have not said whether the suspect attends the school. Those questions remain part of the ongoing investigation as authorities piece together what led to the confrontation.
Video recorded on cellphones captured chaotic moments of the disturbance, with bystanders in caps and gowns visible as people scrambled to get away. Some footage shows a person on the ground being attacked by a group while another individual tries to come to their defense, and other clips offer different angles of the same violent sequence. The presence of graduation attire in the crowd underlines how quickly a celebratory event turned threatening.
Westmoor High School Principal Victor Zou issued a statement saying school officials “are cooperating fully with law enforcement. We understand this news is deeply upsetting for our students, families, staff, and community. Our thoughts are with all those impacted by this incident,” and the administration emphasized its cooperation as officers continued their work. The statement did not specify whether the arrested teen is enrolled at the school, but it did note that the victim does not have a relationship with the district. Families and staff were left searching for reassurance while investigators followed leads from video and witness reports.
KTVU has received videos of violence on campus from separate sources. The chaotic moments of a fight breaking out on an outdoor basketball court are captured. One video shows a person on the ground being attacked by a group and someone coming to their defense. The person who came to the defense is also attacked.
Later in the video, two people who are fighting are pulled apart. One of them appears to be bleeding profusely from their face and torso. By the end of this video, police arrive on the scene and chase people involved in the fight on foot.
Someone can be seen trying to intervene to break up the fight. There are plenty of bystanders, some are wearing their caps and gowns.
Other videos show different angles. One person in the background can be heard saying, “Get these punks out of our school.” Others can be heard calling for some type of security intervention.
Investigators are asking anyone with information to come forward and share what they know to help establish a clearer timeline and motive for the altercation. Police provided a contact number for tips and further leads so they can follow up on any witness statements or additional footage that might surface. Community members have been urged to avoid sharing graphic clips that could hinder the investigation or harm those involved.
Officials stressed that school events should be safe and that the district will review security and protocols in the wake of the incident, even as authorities complete their immediate casework. Parents and graduates deserve an environment where milestones are honored without fear of violence, and local leaders will likely face questions about prevention and response as more details emerge. For now the priority remains the victim’s recovery and a thorough investigation into how a graduation ceremony became the scene of a serious assault.
