The F.B.I. said there were about 12 threatening calls made to the paper.
“Why don’t you call Mueller, maybe he can help you out, buddy,” Mr. Chain said, referring to the special counsel, Robert S. Mueller III, who is investigating Russian interference in the 2016 election. Again using profane language, he threatened to shoot Globe employees in the head.
That threat prompted The Boston Globe to contract with a private security firm, and officers with the Boston Police Department were dispatched to the newspaper’s office.
A statement released by Jane Bowman, a Boston Globe spokeswoman, said, “We are grateful to the F.B.I., the U.S. Attorney’s Office, the Boston Police, and local authorities in California for the work they did in protecting the Globe while threats were coming in, for investigating the source, and for making this arrest. We couldn’t have asked for a stronger response.” She added that, “while it was unsettling for many of our staffers to be threatened in such a way, nobody — really, nobody — let it get in the way of the important work of this institution.”