(NewsNation) — Billionaire Tesla CEO Elon Musk has filed paperwork to terminate his $44 billion agreement to buy Twitter, again. This time, he cited information based on the complaint filed by the Twitter whistleblower.

In an SEC filing Tuesday, Musk said his legal team notified Twitter of “additional bases” for ending the deal on top of the ones given in the original termination notice issued in July.

In a letter to Twitter Inc., which was included in the filing, Musk’s advisors cited the whistleblower report by the company’s former head of security and federal whistleblower Peiter Zatko — also known by his hacker handle “Mudge.”

Musk’s legal team subpoenaed Zatko, who earlier this month told U.S. officials that Twitter misled regulators about privacy and security flaws, on Saturday.

Among Zatko’s most serious accusations is that Twitter violated the terms of a 2011 FTC settlement by falsely claiming that it had put stronger measures in place to protect the security and privacy of its users.

He also accused Twitter CEO Parag Agrawal of misleading Musk and the public about the number of spam accounts on the platform and how the platform counts them. 

The letter, addressed to Twitter’s Chief Legal Officer Vijaya Gadde, said Zatko’s allegations provide extra reasons to end the deal if the July termination notice “is determined to be invalid for any reason.”

“Mr. Zatko’s allegations of widespread security failures and foreign state actor interference at Twitter raise serious concerns.  If these claims are accurate, they may show dangerous data privacy and security risks for Twitter users around the world,” Senate Judiciary Chairman Dick Durbin (D-Ill.) and ranking member Sen. Chuck Grassley (R-Iowa) said in a joint statement. 

Musk has spent the last few months alleging the social media giant has undercounted its use of spam and robot accounts. Now, he is demanding documents and communications to support those claims.

“Musk will have an opportunity to ask him questions and with hopes that he has, that it will help his case, and at the same time Twitter will also be able to push him as well,” Brian Quinn, a professor of law at Boston College, said.

Twitter hasn’t commented on the subpoena.

But earlier this month, the social media giant described Zatko as a disgruntled former employee, fired for his ineffective leadership and poor performance.

The company called his accusations a “false narrative” and “opportunistic,” saying that security and privacy are Twitter’s top priorities.

The attorneys representing Zatko say they exhausted all other channels to correct these revelations before going to law enforcement.

The former hacker turned company executive was fired back in January.

The Hill and the Associated Press contributed to this report.