German police outside the synagogue in Hagen following a tip-off regarding a potential Islamist terror attack on Yom Kippur. Photo: Reuters/Roberto Pfeil/dpa

A 16-year-old Syrian boy was set to appear before a judge in Germany on Friday after he was arrested with three members of his immediate family over a threatened attack against a synagogue as Jews marked Yom Kippur, the holiest day in their calendar, on Thursday.

The unnamed minor was the only family member to remain in custody on Thursday night in the wake of a major police deployment around the synagogue in Hagen, a city just east of Dusseldorf in the state of North-Rhine Westphalia.  The 16-year-old’s father and two brothers were also taken into custody, but were released later on Thursday after police concluded that there was no evidence of their involvement in a crime. The family reportedly arrived in Germany in 2014 as refugees from the civil war in Syria.

In a statement following the arrests, Armin Laschet — the state premier of North Rhine-Westphalia and the main candidate for the center-right CDU Party in Germany’s Sept. 26 federal election — said that the planned attack was motivated by Islamist ideology.

“It appears that prior to today on Yom Kippur, an Islamist motivated attack was averted,” Laschet said. He said the local authorities would “do everything we can to clarify which networks may have been behind” the plot.

German media outlets reported that the 16-year-old in custody had admitted to being in contact with a bomb-making specialist on the Telegram social media channel, but denied that there was a plan to attack the synagogue in Hagen specifically.

The specialist was reported to have been an ISIS operative. Germany’s foreign intelligence service was tipped to the contact by a “foreign secret service,” the Jüdische Allgemeine newspaper reported.

The Dusseldorf prosecutor’s office said that no bomb components had yet been discovered by investigators. Cell phones and computer hard drives had been seized and were being evaluated, a spokesperson said.

German authorities came under severe criticism in October 2019 when two people in the city of Halle were murdered by a neo-Nazi gunman, Stephan Balliet, who attempted to massacre worshippers observing Yom Kippur at a local synagogue. The synagogue’s security doors prevented Balliet from gaining access to the interior of the building, where more than 50 people had gathered. Following the outrage, several experts charged that the synagogue had been poorly protected by local police.

Sabine Leutheusser-Schnarrenberger — the state official tasked with combating antisemitism in North-Rhine Westphalia — congratulated the police for “quickly recognizing” the threat in Hagen on Thursday and responding appropriately. She added that planning an attack on Jews as they observed the Yom Kippur fast was “particularly reprehensible.”

Meanwhile, a Jewish culture and music festival scheduled to take place at the synagogue in Hagen will go ahead on Sunday as planned. Manfred Keller, the director of the festival, confirmed on Friday that Hagen police had told him there were “no indications of any real threats.”