In this photo illustration, a phone screen displays the Twitter account of Elon Musk with a photo of him shown in the background, on April 14, 2022, in Washington, DC. (OLIVIER DOULIERY / AFP)

WILMINGTON, Deleware - Elon Musk has subpoenaed a Twitter Inc whistleblower, seeking documents and communications on the company's spam and alleged security vulnerabilities as the billionaire battles to end his agreement to buy Twitter for $44 billion, according to a court filing on Monday.

Elon Musk also sought documents and communications about alleged attempts to hide security weaknesses, compliance with a 2011 Federal Trade Commission agreement and "Twitter's engagement in any unlawful activity"

Musk sought information from whistleblower Peiter Zatko mostly about the way Twitter measures spam accounts. Musk has said he is walking away from the deal for the company because Twitter misled him and regulators about the true number of spam or bot accounts on the microblogging platform.

But Musk also sought documents and communications about alleged attempts to hide security weaknesses, compliance with a 2011 Federal Trade Commission agreement and "Twitter's engagement in any unlawful activity."

A spokesman for Twitter declined to comment.

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A famed hacker widely known as "Mudge," Zatko ended a stint as the head of Twitter's security earlier this year, and said in his whistleblower complaint that became public last week that the company falsely claimed it had a solid security plan.

A sign is seen outside the Twitter headquarters in San Francisco on April 25, 2022. (JED JACOBSON / AP)

The information that Musk obtains from Zatko might lay the groundwork for the Tesla Inc chief executive to introduce new fraud claims in his legal battle with Twitter, according to Ann Lipton, a professor at Tulane University Law School.

A famed hacker widely known as "Mudge," Peiter Zatko ended a stint as the head of Twitter's security earlier this year, and said in his whistleblower complaint that became public last week that the company falsely claimed it had a solid security plan

However, she said it was unclear if the judge in the Twitter litigation would allow Musk to introduce those claims given the tight schedule for the case and because Musk waived due diligence before signing the deal contract.

A Twitter attorney said at a court hearing last week that Musk's focus on spam as a way to end his agreement to buy the company was "legally irrelevant" because Twitter always said its spam counts were only estimates, not binding representations.

READ MORE: Musk sells Tesla shares, cites potential forced Twitter deal

The two sides have sued each other and are heading to a five-day trial on Oct 17. Musk wants out of the deal and Twitter is asking Chancellor Kathaleen McCormick of the Delaware Court of Chancery to order him to buy the company for the agreed $54.20 per share.

Twitter's stock ended down 1 percent at $40.04 on Monday in New York.