Officials responded to a report of felony vandalism at 11:43 a.m. Sunday. They said the suspects sprayed 49 locations on campus with graffiti. Some of the writings said "white power," according to authorities.
There appears to be more than one suspect based on the extensiveness of the vandalism, investigators said.
Crews were trying to clean up the graffiti on Monday. It was not immediately known how much progress was made.
It's the second time in five months that Reilly Elementary has been hit by vandals.
Anyone with information was asked to call the Orange County Sheriff's Department at (714) 628-7170.