Officers responded to Marlborough School, located in the 200 block of Rossmore Avenue, Friday afternoon after LAPD says the school received a "telephonic threat" at about 1:10 p.m.
The school was placed on lockdown as LAPD investigated the campus.
The lockdown was lifted by 4 p.m., and students were released from the school after being evacuated earlier.
Further details about the threat were not immediately known. LAPD's Bomb Squad responded to the scene and remained on the property Friday evening as they continued their sweep.
Some students told Eyewitness News that their phones were locked inside Yondr pouches during the lockdown, making it hard to get updates. One parent told ABC7, at the scene, that she received a message from the school telling her not to come.
"We got a notification on a text that there was a lockdown. There was a called in bomb threat to the school. I didn't read the whole thing because it said don't come. So I immediately jumped in my car and, we don't live far, and then got here and that was it."
The parent's statement was interrupted by a school administrator, who told her to stop speaking with our ABC7 crew despite being on public property. The school has not provided any information or details about the incident.
Other parents told Eyewitness News off camera that they were discouraged from speaking about the incident.
LAPD has not said what the threat specifically involved or whether they've identified anyone responsible.
This incident is the second threat against a SoCal school on Friday.
Earlier in the day, a report of a possibly armed man at Walter Reed Middle School in North Hollywood prompted a lockdown on that campus. It was later determined to be swatting incident.