Facebook CEO Mark Zuckerberg has been listed as a defendant in a privacy lawsuit stemming from a complaint over the Cambridge Analytica scandal. The new filing signifies the first time any U.S. regulator has named Zuckerberg in a complaint, according to District of Columbia Attorney General Karl Racine’s office. In a Wednesday Twitter thread, Racine said that his team’s “continuing investigation revealed that [Zuckerberg] was personally involved in decisions related to Cambridge Analytica and Facebook’s failure to protect user data.”

In a statement, Racine said Zuckerberg had “knowingly and actively” allowed Cambridge Analytica, the political consulting firm, to scrape private data from more than 87 million users. A major Facebook product change in 2010 that allowed third-party developers access to sensitive user data, for instance, was Zuckerberg’s own “brainchild.” Racine said that, given the evidence collected by his office, “adding Mr. Zuckerberg to our lawsuit is unquestionably warranted.” A Facebook spokesperson called the allegations “as meritless today as they were more than three years ago, when the District filed its complaint.”