A swastika and antisemitic slogans were scratched on the wall of a kosher cafe in Hendon Park on Monday night.
Hendon Park Cafe owner Jason Ezekiel was informed of the graffiti by a park keeper. "He had already painted over some of it as he didn't want to upset Jewish people. I am very distraught by the whole thing."
Mr Ezekiel believed the perpetrator used a key. "It must have taken at least 20 minutes to do."
Community Security Trust communications director Mark Gardner said: "This was a particularly ugly incident in a peaceful location that is popular with many families."