The arrest of an Israeli-American teenager in Ashkelon on Thursday, March 23, might resolve the bomb threats made this year against the Marcus Jewish Community Center and dozens of other JCCs and Jewish institutions, but it does not mean organizations should reduce their vigilance.

“While Atlanta Initiative Against Anti-Semitism is pleased another suspect has been arrested in connection with threats targeting JCCs, anti-Semitism across the U.S. remains a very serious problem. It is critical that communities stand in solidarity to denounce and combat hatred and terrorism,” AIAAS said in a statement released after the arrest of a Jewish suspect exactly one week before the new organization’s first meeting at Temple Emanu-El.

The suspect, whom Israeli news outlets were blocked from identifying, is 18 or 19 years old. Israeli authorities arrested him at the request of the FBI, The Forward reported, after an investigation involving both countries that began after the first of at least six waves of bomb threats against JCCs, including the Marcus JCC, in early January.

“Today’s arrest in Israel is the culmination of a large-scale investigation spanning multiple continents for hate crimes against Jewish communities across our country,” Attorney General Jeff Sessions said in a statement. “The Department of Justice is committed to protecting the civil rights of all Americans, and we will not tolerate the targeting of any community in this country on the basis of their religious beliefs. I commend the FBI and Israeli National Police for their outstanding work on this case.”

The suspect is being held for at least eight days as the investigation continues. It is not clear whether he will be extradited to the United States or will stay in Israel to face extortion charges.

His public defender, Galit Besh, said the young man has a serious medical condition — identified by Israel’s Channel 10 as a nonmalignant brain tumor going back to at least age 14 — and it could affect his behavior, The Times of Israel reported.

“He’s the guy who was behind the JCC threats,” Israeli police spokesman Micky Rosenfeld said, according to The Times of Israel.

More than 160 fake bomb threats have been made against Jewish institutions in the United States and Canada since Jan. 9, the day the Marcus JCC and 15 other JCCs received threats by phone. The Marcus JCC received an email threat March 15.

The JCCs in Birmingham and Nashville also have been threatened multiple times, and the centers in New Orleans, Charlotte and Augusta are among the others to get threats during at least six waves of calls and email messages.

The Israeli suspect also has been linked to bomb threats in Australia and Europe and against a Delta Air Lines flight in February 2015.

He used a sophisticated array of technical equipment and anonymous accounts to disguise his identity and the origins of his calls and email messages, but he slipped up at least once and failed to route his Internet connection through a proxy server, revealing that he was in Israel, The Daily Beast reported.

He is not being blamed for all the U.S. threats — a disgraced St. Louis reporter was arrested March 3 in connection with a few hoax threats meant to get an ex-girlfriend in trouble, the FBI said — and he had nothing to do with toppled Jewish tombstones and other anti-Semitic vandalism in the United States.

“Even though it appears that the main culprit behind the majority of these attacks has allegedly been identified, anti-Semitism in the U.S. remains a very serious concern,” Anti-Defamation League CEO Jonathan Greenblatt said in a statement. “No arrests have been made in three cemetery desecrations or a series of other anti-Semitic incidents involving swastika graffiti and hate fliers.  JCCs and other institutions should not relax security measures or become less vigilant.”

JCC Association of North America President and CEO Doron Krakow thanked law enforcement for vigilance in the investigation and acknowledged being troubled at the suspect’s Jewish identity.

“Emblematic of the strength of JCCs and the important model they represent for acceptance, inclusion and appreciation for diversity is the remarkable support we have received from communities and community leaders across North America, including civic, political and faith community leaders,” Krakow said. “Throughout this long-running period of concern and disruption that we are hopeful has come to an end, JCCs have had the opportunity to review and assess our security protocols and procedures, and we are confident that JCCs are safer today than ever before.”

The Secure Community Network, a project of the Jewish Federations of North America and the Council of Presidents of Major American Jewish Organizations, announced two days before the arrest that it had hired counterterrorism expert Charlie Payne in response to the bomb threats.