Police say they have released photos of the suspect behind the anti-Semitic and hateful graffiti painted on the back of Syosset High School.
They say surveillance images show a 17-year-old girl wearing a tank top and black costume mask.
As News 12 has reported, swastikas, profanities and the words "MS-13" were found on the walls, doors and windows of the school.
Officials are offering a $5,000 reward for anyone who can help identify the suspect.
Anyone with information is asked to call police.