You would be surprised how frequently anti-Semitic incidents occur. Most cases are not solved. Brockton police will soon come out with an indictment. The age age of perpetrators ranges from 15 to 25. Usually the perpetrators are white.
Religion is immaterial.
Sometimes Jewish kids are involved, self-hating Jews who become involved with skinheads, who are confused. Not many incidents are violent. Most people who experience anti-Semitism have qualms about going public. I usually have a conversation with them about the pros and cons. If you don't go public, no one knows that you are facing this kind of situation.