A 19-year-old with dual American-Israeli citizenship has been arrested in connection with recent bomb threats on Jewish Community Centers, according to a report in The Jerusalem Post.

At least 145 bomb threats have been made to Jewish centers since January 1st. It’s unclear how many of the threats today’s arrestee was responsible for, but investigators are treating him as a central suspect. “He was the main suspect behind the numerous amount of threats which were made to different Jewish communities and organizations around the world,” investigators told the Post.

Investigators confirmed that the suspect was using anonymizing methods to hide his identity, and it is still unclear how they were able to locate him. The structure of the US phone system makes it difficult to trace anonymous calls made to US locations, particularly if the calls were routed through a compromised phone system.

While the majority of the threats targeted US centers, investigators discovered today’s arrestee by tracing the origin of a threat called into a New Zealand facility in 2016. The suspect will be indicted in Israeli court, although the United States may seek extradition.

Earlier this month, disgraced journalist Juan Thompson was arrested in connection with a smaller number of threats, some of which were made in his name. Those incidents appear to have been part of a harassment campaign against Thompson’s ex-girlfriend, and unrelated to the larger wave of threats.