Left: Gil Cisneros; right: Andy Thorburn (AP)

Two Democrats in a blue-trending California congressional district locked horns Friday over a short piece of audio — a voice mail that candidate Andy Thorburn claims candidate Gil Cisneros left on his wife’s phone. By the end of Friday, the dust-up had led to legal action, accusations of fraud and one candidate comparing the other to President Trump.

The voice mail, first reported by the Intercept, is just a few seconds long. In it, a man identifies himself as Cisneros, a candidate in California’s 39th Congressional District, and informs Thorburn that “I’m gonna go negative on you.”

The Intercept, which has been closely covering brawls in Democratic primaries, reported on the voice mail Thursday afternoon. On Friday morning, Cisneros’s campaign released the cease-and-desist letter it had sent to the Intercept, claiming that the story was “false and defamatory” and further claiming that the audio had been faked.

“The voice on that recording is not Gil Cisneros, plain and simple,” said Cisneros spokesman Orrin Evans. “The Intercept’s ‘story’ about a voice mail — apparently provided to them by the Thorburn campaign — is completely false and manufactured. The Intercept posted the fabricated voice mail without even playing the recording for the Cisneros campaign to verify his voice, and took no steps to authenticate the recording prior to its release.”

The story stayed online, as of the deadline, 3 p.m. Pacific time, that the Cisneros attorneys had set. The campaign has said it will sue the Intercept if the magazine does not respond to its requests about how the voice mail was authenticated. The magazine’s attorneys responded Thursday with a letter standing by the story and saying that Cisneros had refused to respond to questions until after the story ran.

“Multiple sources familiar with Mr. Cisneros identified the voice as the candidate’s voice,” the Intercept’s legal team wrote. “The context, including the fact that Mr. Cisneros’s campaign did, in fact, go negative soon thereafter, supports the authenticity of the tape message.”

The Thorburn campaign, meanwhile, responded by mocking the Cisneros campaign. Cisneros, a lottery winner and veteran who has been named one of the Democratic Congressional Campaign Committee’s “Red to Blue” candidates, had indeed launched some negative attacks on Thorburn; that was enough for the campaign to dub the legal threat “typical Trump-like tactics,” accusing him of going after the free press to “silence their First Amendment rights.”

“When I got home one evening, I checked our voice mail and heard this,” Karen Thorburn said in a statement released by the campaign. “I’ve heard Gil speak at a lot of forums and it sounded like him to me! I thought it was bizarre so I notified the campaign staff.”

On Twitter, Thorburn mocked Cisneros by invoking “John Barron,” the pseudonym that President Trump used to lobby reporters for positive coverage during his career in New York.

The 39th Congressional District is seen as one of the Democrats’ best potential pickup opportunities in 2018, so long as a Democrat makes it out of the top-two primary system. Six Democrats are running in the June 5 primary, as well as six Republicans; polls released by Cisneros campaign have shown him leading the field, with just 19 percent of the overall vote.