Two students — a 16-year-old girl and a 14-year-old boy — died in a mass shooting that left four others injured at Saugus High School in Santa Clarita, Calif., on Thursday, authorities said.

The suspected gunman, a 16-year-old male student at the high school, was among those injured, Los Angeles County Sheriff Alex Villanueva said at a news conference Thursday afternoon. Officials said the suspect shot himself and was in “grave condition,” though they did not specify the hospital where he’s being held. The shooting caused chaos at the high school, located about 40 miles north of Los Angeles, as students scrambled for safety amid the melee, and frantic parents urgently sought to reunite with their children.

Here’s what to know about the shooting at Saugus High School.

The shooting happened around 7:30 a.m. local time, near the start of the school day, authorities said. Kent Wegener, captain of the L.A. County Sheriff’s homicide bureau, said police arrived at the scene to find six people suffering from gunshot wounds in the school’s quad area. The students were taken to a local hospital, where officials later discovered the shooting suspect was among those who had been injured.

During a Thursday afternoon press conference, an emergency services official indicated his team “treated, triaged and transported seven patients,” in total, but were well-equipped to do so, with “a total of 65 units.” Six victims were transported by ambulance, and one was transported by helicopter. One of the transported victims was not injured by gunfire, the official said.

Wegener said the suspected gunman was in the quad when he pulled out a .45-caliber pistol from his backpack and began shooting the other students before shooting himself.

Saugus High School and other schools in the William S. Hart school district were put on lockdown Thursday morning, though most of the lockdowns were lifted by the afternoon. Authorities began an immediate search for the shooter, and looked at the neighborhoods near the school, thinking the suspect ran away from campus after opening fire.

Local TV showed a chaotic scene at Saugus High School, as students were escorted out of the school and authorities spread around the campus to offer help. Several students said they were barricaded in classrooms while they waited for police to apprehend the shooter.

Shauna Orandi, a student at the high school, told the Associated Press she was working on homework in her Spanish class when she heard gunshots. Orandi said she told herself, “This is it. I’m going to die.” The AP reports she was later reunited with her father.

Parents were directed to Central Park on Bouquet Canyon Road to reunite with their children.

Brian Skiba, a parent of one of the students at the high school, told KCBS he reunited with his son at a meeting place they both have.