What to Know 69-year-old Robert Chain of Encino, California, was charged with making threatening communications in interstate commerce.

FBI says Chain called the Globe "the enemy of the people" in phone calls and threatened to go to Boston to kill employees from Aug. 10-22.

A "significant" amount of guns have been found at Chain's home, according to multiple law enforcement officials.

A California man was arrested Thursday and charged with making threats against The Boston Globe over the newspaper's campaign to defend the free press, authorities said.

Sixty-eight-year-old Robert Chain of Encino, California, was arrested by FBI agents on a charge of making threatening communications in interstate commerce.

A "significant" amount of guns have been found at Chain's home, according to multiple law enforcement officials.

"What makes America so great is the freedom of the press, and being able to express yourself that way, so we're going to make sure... any threats, we're gonna work on," said Boston Mayor Marty Walsh.

Chain allegedly called the Globe "the enemy of the people" in phone calls and threatened to travel to Boston to kill newspaper employees. He made approximately 14 threatening phone calls to the Globe from Aug. 10, when the Globe announced its campaign, to Aug. 22, according to court documents.

Chain is due in federal court in Los Angeles Thursday. It was not immediately clear if Chain had an attorney who could answer to the charge, which would carry a sentence of up to five years in prison and a fine of $250,000.

Court documents state on the day the coordinated editorial was to publish, which was Aug. 16, Chain allegedly threatened to shoot Globe employees "later today, at 4 o'clock."

As a result of the threat, law enforcement responded to the newspaper's building to ensure employees were safe.

"Everyone has a right to express their opinion, but threatening to kill people, takes it over the line and will not be tolerated," said Harold H. Shaw, Special Agent in Charge of the Federal Bureau of Investigation, Boston Division, in a statement.

The Globe led hundreds of newspapers around the country this month in a campaign to push back against President Donald Trump's cries of "fake news" that is an “enemy of the people."

The newspaper’s editorial on the campaign concluded: "The greatness of America is dependent on the role of a free press to speak the truth to the powerful. To label the press 'the enemy of the people' is as un-American as it is dangerous to the civic compact we have shared for more than two centuries."

While some news outlets opted out of joining the campaign, ones that did included The New York Times, Miami Herald and Houston Chronicle.

The campaign prompted Trump to lash out against the Globe on Twitter, saying it was "in COLLUSION with other papers on free press."

In a statement, Jane Bowman, Boston Globe's vice president of marketing and strategic partnerships, said the newspaper was "grateful" for protecting its employees.

"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," Bowman said.