In a filing on Friday afternoon with the US Securities and Exchange Commission (SEC), Musk's team claimed he had terminated the deal because Twitter was in "material breach" of their agreement and had made "false and misleading" statements during negotiations.
"For nearly two months, Musk has sought the data and information necessary to make an independent assessment of the prevalence of fake or spam accounts on Twitter's platform'," Musk's legal team wrote.
"Twitter has failed or refused to provide this information," they added.
Twitter board chairman Bret Taylor wrote that the company will "pursue legal action to enforce the merger agreement" and feels "confident we will prevail" in court.
Musk has been setting the stage to abandon the deal just weeks after he signed the agreement, claiming that Twitter released misleading stats about the prevalence of spam bots on its platform.
It is entirely unclear, however, that Musk can legally abandon his agreement simply because he isn't happy about the presence of spam on Twitter, something he could have investigated before signing the deal.
Twitter has gone to great lengths to show compliance with Musk's requests.
In early June, the company opened up "firehose" access to its service so that Musk could receive and analyze every tweet as it was posted. The company has also continuously tried to reassure the public that it has spam and bots under control.
On Thursday, it told the press that it was blocking over a million spam accounts per day, and in May, its CEO wrote a long thread about how Twitter determines how many of its users are bots.