The victim suffered a gunshot wound to his shoulder area and was hospitalized in stable condition, Los Angeles County Sheriff's Jim McDonnell said at an afternoon news briefing.
Officials said they received a call about a man with a gun on the high school's campus.
In the end, there was just one shooting and one victim, at Highland High School, about 40 miles (64 kilometres) northeast of Los Angeles.
The boy injured was also 14, and police stated that he was taken to the hospital after being shot in the arm.
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"Everyone expected it when two of the top teams from the league are playing each other", Jets center Paul Stastny said . Rinne played one of his best games of this series against the Jets, after being pulled in the last game at home .
The suspect was a "male Hispanic juvenile", the sheriff's office said, later clarifying that the weapon was a rifle that was "recovered off campus".
Officials said deputies searched the elementary school and found no evidence of a shooting. The campus, at 39055 25th Street West, was initially placed on lockdown along with all other schools in the Antelope Valley Union High School District.
"We barricaded the room", she said. "Alexander, turn around, turn around, there's an active shooter.' And I didn't really have time to react to that because nearly immediately after that I heard one single gunshot very loud and very close by".
It is unknown why or when the student was pulled from the school or if he had previous issues with officials.
70s expected today with mostly sunny skies
Night: mostly cloudy to overcast with a 60 percent chance for showers with between one-tenth and one-quarter inch expected. Mostly cloudy, with a low around 66. - Several rounds of wet weather now appear possible through the weekend.
Reports of the shooting and an ultimately false report of another attack at a nearby elementary school sparked chaos, terrifying parents and drawing a massive police response in the high desert city of Palmdale in Southern California. Earlier, the department tweeted that that a "possible shooting" was reported around 7:00 a.m. PT. The arresting officer is a family friend, McDonnell said.
Highland High School is located about 65 miles from Los Angeles.
McDonnell said the sheriff's Palmdale Station fielded almost 100 calls in the minutes after the shooting. "He shot me! I don't know why he shot me!"
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Melania Trump outlined her new initiatives, known as the Be Best program, during the event. Pence said that was a "private matter" and "something I don't have any knowledge about".