A former journalist fired for fabricating details in stories made at least eight of the dozens of threats against Jewish institutions in the United States, as part of a bizarre campaign to harass and frame his ex-girlfriend.
Juan Thompson was arrested in St Louis and appeared on Friday in federal court on a cyberstalking charge.
Federal officials have been investigating 122 bomb threats called in to Jewish organisations in three dozen states since January 9, and a rash of vandalism at Jewish cemeteries.
A criminal complaint said Thompson started making threats January 28 with an email to the Jewish History Museum in New York, written from an account that made it appear as if it were being sent by an ex-girlfriend.
"Juan Thompson put 2 bombs in the History Museum set to go off Sunday," it said.
Authorities said he followed that up with similar messages to a Jewish school in Farmington Hills, Michigan, and to a school and community centre in Manhattan.
In another round of emails and phone calls, he gave the woman's name, rather than his own, the court complaint said.
The Council on American-Islamic Relations received an anonymous email saying the woman put a bomb in a Dallas Jewish centre.
Thompson, who's black, then took to Twitter: "Know any good lawyers?" he wrote. "Need to stop this nasty/racist #whitegirl I dated who sent a bomb threat in my name."
He later tweeted to the Secret Service: "I'm been tormented by an anti-Semite. She sent an antijewish bomb threat in my name. Help."
But police say it was a hoax created to make the woman look guilty.
President Donald Trump suggested this week that the threats against Jewish community centres may have been designed to make "others look bad".
Thompson was fired from the online publication The Intercept last year after being accused of fabricating several quotes and creating fake email accounts to impersonate people, including the Intercept's editor-in-chief.
According to the criminal complaint, Thompson and the ex-girlfriend, a social worker, broke up last summer.
The following day, her boss received an email purporting to be from a national news organisation saying she'd been pulled over for drunken driving.
The harassment got worse, authorities said. She received an anonymous email with nude photos of herself and a threat to release them.
Her company, a non-profit that works to end homelessness, got faxes saying she was anti-Semitic.
Meanwhile, the National Center for Missing and Exploited Children got a note saying she watched child porn.