Two large swastikas were spray painted outside the Congregations of Ner Zedek in northeast Philadelphia Sunday night, JTA reports. The city sent a maintenance team to remove the graffiti when congregants discovered it Monday morning. Congregants began poring over footage recorded by the synagogue’s recently-installed security cameras, hoping to identity a suspect.

According to Fox 29 News, the Conservative congregation includes many elderly members, some of them Holocaust survivors. “I have a number of Holocaust survivors here in my congregation, and if they see something like this. Of course it brings back all sorts of terrible memories of what they went through,” the synagogue’s rabbi, Reuben Israel Abraham, told reporters.

According to Philadelphia’s Jewish Exponent, an Anti-Defamation League report released in April revealed a rise in anti-Semitic incidents the previous year, with a total of 45 incidents reported.

FOX 29 News Philadelphia | WTXF-TV