The Thursday night incident comes with Rosh Hashana about to begin at sundown Friday, Sept. 15 -- and amid a frightening nationwide increase of anti-Semitic "swatting" calls.
A caller to the Fair Lawn Police Dispatch Center at 8:01 p.m. Sept. 14 claimed to have planted both bombs in a black backpack at Congregation Ahavat Achim on Saddle River Road, Sgt. Eric Eleshewich said.
Police cleared the building and neighboring homes, and the Bergen County Sheriff's Bomb Squad conducted an intensive search inside and outside, the sergeant said.
They "found no evidence of a bomb or material that could be used to make a bomb," Eleshewich said.
Also responding were Fair Lawn firefighters, the Heavy Rescue Squad, the Fair Lawn Volunteer Ambulance Corps and sheriff's officers, the sergeant said.
The U.S. has seen a terribly disturbing rise this summer in the number of anti-Semitic "swatting" incidents, so named for the tactical squads that ordinarily respond to the calls.
Over only a one-month period, the Anti-Defamation League reported 26 calls threatening violence at synagogues in a dozen states stretching from one end of the country to the other.
The hoaxers claim that someone is shooting up a synagogue or that a bomb has been planted there.
Although they can't be sure, authorities believe white supremacists are mostly to blame.
In some cases, the swatters have targeted synagogues that livestream services, police say, so that they can watch -- and record -- officers in combat gear removing frightened worshippers in real time. They then post snippets of the recordings online.
Jonathan A. Greenblatt, the ADL's CEO and national director, referred to the callers last month as "trolls who swat and call in fake bomb threats targeting synagogues."
"The trolls use highly antisemitic language in these calls," he noted.
"The ADL Center on Extremism continues to work with law enforcement to determine the source or sources of these troubling and potentially dangerous activities," Greenblatt said.
The FBI has been working with local law enforcement to try and trace the calls. Police departments have also boosted their presence in synagogue neighborhoods.
Boyd A. Loving took the photo and contributed to this story.
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