SAN FRANCISCO (KCBS) – The FBI has launched a hate crime investigation after Jewish community centers in North America, including the Bay Area, received 60 bomb threats in the past month.

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While the bomb threats have been disruptive, they have so far been hoaxes.

David Posner with the JCC Association of North America says most of the phone calls are believed to be from a woman, at times using voice disguising technology.

“Yes, we are concerned about anti-Semitism. They are definitely targeting JCCs,” Posner told KCBS.

In the Bay Area, calls were made in mid-January to a JCC in San Rafael and a Jewish Day School in Foster City.

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This week in California, two JCC’s received bomb threats in La Jolla in San Diego County and Long Beach.

“The FBI has opened an investigation,” Posner said.

And the FBI has labeled these bomb threats as hate crimes, not terrorism. Security protocols are in place at all Jewish facilities.

“They have acted professionally, coolly, calmly from start to finish, and they will continue to do so, and hopefully they will never have to do so again,” Posner said.

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The bomb threats have come in waves in several states, on January 9, January 18th and January 31st.