The shooting was reported near Rimpau and Olympic boulevards at approximately 3:30 p.m.
A 17-year-old and 18-year-old were reportedly shot. They were treated at the scene and hospitalized. It was originally reported the 18-year-old was 20.
The 17-year-old is reportedly a student at the school; the other victim is not.
By 5:30 p.m., police said they were only searching for one suspect, and said a description was not available.
Four young men, described by police as "people of possible interest in the crime," were reportedly detained near Olympic and Arlington Ave.
Earlier, police were searching for two suspects: a Hispanic male with short spiky black hair, standing 5 feet 7 inches tall, weighing 130 pounds, wearing a gray shirt and blue jeans; and a Hispanic male with a shaved head, standing 5 feet 5 inches tall, weighing 120 pounds, wearing a white shirt and blue jeans.
Los Angeles Unified School District officials said the two were not shot on campus.
Eyewitness News interviewed several students, who all thought the shooting must be gang-related. Police did not speculate about the motive.
Los Angeles Senior High School was not locked down.