Three people are in custody and one person was injured in an incident involving a firearm at Balboa High School in San Francisco Thursday, according to police.
The incident was reported at 11:15 a.m. at the school at 1000 Cayuga Ave., but police and school district officials have not clarified exactly what happened.
The police response prompted the lockdown of Balboa High, as well as neighboring James Denman Middle School, Leadership High School and San Miguel Early Education School.
One person suffered an injury not believed to be life-threatening at the school, but police did not clarify how the injury occurred.
The lockdowns have since been lifted and students who take transportation independently have been allowed to leave the campus, according to the San Francisco Unified School District.
District officials said parents and guardians who know their students are waiting for them should meet them at the school’s football field.