US prosecutors in New York have charged a Missouri man in connection with at least eight bomb threats made against Jewish organisations across the country.
Juan Thompson, 31, was taken into custody on Friday morning (local time) in St Louis and was expected to make an initial court appearance there later in the day.
It was not immediately clear whether investigators believe Thompson is responsible for all of the more than 100 threats that have been made by phone to Jewish community centres in dozens of states since January.
In a criminal complaint filed in federal court in Manhattan, authorities accused Thompson of making at least eight threats, mostly by email.
Prosecutors said Thompson made the threats in an effort to harass a former girlfriend by telling the Jewish groups she was the person behind the alleged bombs.
Jewish community centres and schools in the United States have received five waves of hoax bomb threats this year, stoking fears of resurgence in anti-Semitism.
Based on Thompson's Twitter account, which provided some of the evidence cited in the criminal complaint, the defendant appears to be a former reporter for The Intercept, a news website focused on national security.
Thompson was fired from the website last year for allegedly fabricating quotes and sources, The Intercept said in February 2016.
US President Donald Trump, Israeli officials and Jewish groups have all condemned the surge in intimidation as well as cases of vandalism targeting Jewish cemeteries.
Police said last weekend that about 100 headstones were toppled at a Jewish cemetery in Philadelphia, about a week after a Jewish cemetery in St Louis was vandalised.
Some Jewish groups see the vandalism and threats as a sign that anti-Semitic groups have been emboldened by Mr Trump's election. His campaign last year drew the support of white supremacists and other right-wing groups, despite Mr Trump's disavowals of them.