Elon Musk has subpoenaed a Twitter whistleblower in his ongoing legal battle with the social media platform to end the $44 billion (nearly Rs. 3,51,300) buyout agreement, according to a recent court filing. The SpaceX and Tesla head has sought documents and information on the Twitter’s spam accounts and alleged security vulnerabilities on the microblogging site. This is Musk’s latest move, following his attempts to seek communication on bots from other executives related to Twitter, including head and former CEO Jack Dorsey.

According to court filings, reported by Reuters on Monday, the billionaire has subpoenaed whistleblower Peiter Zatko, who recently raised shocking allegations on Twitter. Zatko, a former head of Twitter’s security, will be asked about how the microblogging site measures spam accounts.

Musk is seeking documents to reveal Twitter’s alleged attempts to hide security weaknesses and compliance with a 2011 Federal Trade Commission agreement. According to the billionaire’s claims, he was misled about the true number of spam or bot accounts on the social media platform.

Twitter and Musk have been engaged in a legal battle ever since the billionaire announced to walk away from their deal. Twitter sued Musk after his announcement, followed by his countersuit against the microblogging site.

Both sides will be heading for a five-day trial starting October 17. While Musk wants to move out of the deal, Twitter has requested the court to order the billionaire to buy the company for the agreed amount.