Authorities said the latest incident happened around 2 p.m. on March 12 near the school on the 9300 block of Noble Avenue.
Witnesses also say they think he is the same man who committed a lewd act near the school.
"This is not some benign, friendly gesture," said Lt. Paul Vernon with the Los Angeles Police Department. "This man has been seen here more than once, and his behavior is troublesome and illegal."
The suspect was described as a Hispanic male between 25 and 30 years old with thick hair. He has been seen driving a black truck similar to a Ford F-150.
Anyone with information on the suspect was asked to call the LAPD's Mission Area Police Station at (818) 838-9967.