When the man realized the student that entered the bathroom had seen him, he ran out and was last seen riding a bicycle away from the school.
The student went back to class and told her teacher about the disturbing encounter.
Covina school officials said they sent students home with letters to inform parents about the incident. Authorities also used an automated calling system.
The superintendent said the safety of the students is a major concern. Las Palmas and other schools have campus security guards on patrol. They will be joined by Covina police on Monday in light of the recent incident.
Police want the public's help to catch the predator. If you have any information, you're urged to call Covina police at (626) 331-3391.
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