Updated June 23 at 3:55 p.m.

It had been more than 40 years since Foster City’s Peninsula Sinai Congregation faced an antisemitic graffiti attack.

That streak ended over the weekend when a nearly 2-foot-wide swastika was discovered spray-painted on the south side of the synagogue.

A congregant out for a late afternoon stroll on Sunday, noticed the vandalism and contacted the synagogue. Foster City police are investigating the incident, which the Anti-Defamation League labeled a hate crime.

“We’re fairly confident it was placed in the early morning hours of Saturday, sometime after midnight,” said Matthew Parks, president of the 55-year old Conservative congregation. “It’s a little disturbing because that meant for the entire day …  people were walking by, with a park across the street. And not until Sunday was it noticed and reported.”

The graffiti, which was painted over the next day, included both a swastika and other symbols of unclear meaning. Parks requested that the image of the symbols be blurred out in photos to avoid amplifying any hidden message.

“For right now, we are following the recommendation of law enforcement and other security professionals to withhold that part of the graffiti,” Parks said.

There was quite a bit of shock and consternation. We came together for Tuesday night minyan, and had a much larger crowd than usual.

Teresa Drenick, interim regional director for ADL’s Central Pacific Region, agreed that blurring the image is the right decision. She said the incident is only the latest amid a spike in antisemitic acts in the Bay Area.

“We know from our annual audit that the number of antisemitic incidents in the Bay Area in 2022 increased at an alarming rate,” Drenick said. “While we don’t have a full count for 2023, antisemitic incidents continue to be on the rise and that includes incidents in all parts of the Bay Area” and places like high schools and colleges. The distribution of antisemitic fliers had continued as well, she said.

Parks said congregants were notified immediately of the incident, as were other local Jewish institutions, including congregations, day schools and JCCs. Foster City police have increased patrols in the area, he said.

“There was quite a bit of shock and consternation,” Park said of the reaction among congregants. “We came together for Tuesday night minyan and had a much larger crowd than usual.”

He appreciated the “outpouring of support” from rabbis and board members of other area synagogues, as well as messages of sympathy from other faith-based institutions. Parks was especially grateful for a vandalism kit the congregation received from Wornick Jewish Day School in Foster City.

“It’s basically a box containing paint, rollers, a tarp and instructions on how to handle incidents of vandalism,” Parks said. “I’m having our security committee and grounds committee add that to our inventory.”

In December 1979, a vandal spray-painted a 3-foot-wide swastika on the outside of the then-new main building of Peninsula Sinai Congregation. In that case, the perpetrator was caught. It was a teenager, who said he didn’t understand the emotional pain of the symbol.

Though the synagogue’s security cameras didn’t catch the weekend’s vandal or vandals in action, Parks said his congregation will remain in contact with the police. So will the ADL.

“We always stay in touch with law enforcement when there is a hate incident, and we will do all we can to partner with the congregation,” Drenick said. “Many antisemitic incidents don’t rise to the level of criminal behavior, whereas this does. It was a hate crime.”

UPDATE: An earlier version of this story said that Peninsula Sinai is 66 years old and that the vandalism kit was provided by the Peninsula JCC. In fact, the synagogue is 55 years old and the kit came from Wornick Jewish Day School.