Tesla CEO Elon Musk has sent an additional letter of deal termination to Twitter Inc after enforcing a subpoena of a whistleblower seeking documents on how the social media company measures spam accounts.

According to a court filing on Monday, Mr Musk has sought information from whistleblower and former head of Twitter’s security Peiter Zatko about the way the microblogging site measures spam accounts.

Last week, Mr Zatko accused the social media platform of “extreme, egregious deficiencies” in its practices around spam and hacker attacks.

Mr Zatko said Twitter violated the terms of an 11-year-old settlement with the Federal Trade Commission by falsely claiming it had a solid security plan.

Mr Musk’s legal team is seeking a deposition and documents from Mr Zatko ahead of its October 17 trial in Delaware’s Chancery Court. Mr Zatko also received a subpoena from Congress in light of the whistleblower complaint and will appear before the Senate Judiciary Committee next month. 

Last week, a judge rejected Mr Musk’s request for another swath of data from Twitter as “absurdly broad” and suggested that the company’s cooperation to date was sufficient.

“My overall impression is that plaintiff has agreed to produce a tremendous amount of information to defendants and that the information plaintiff has agreed to produce is sufficiently broad to satisfy most of the plaintiff’s obligations,” said Chancellor Kathaleen McCormick of Delaware’s Court of Chancery.

Mr Musk walked away from his $44 billion buy-out offer for Twitter in July, saying Twitter did not reveal the actual number of spam or bot accounts on the microblogging platform. In return, Twitter sued Mr Musk, pressuring him to follow through with the acquisition agreement.