Facebook investors pushed back last week against Facebook directors' motion to dismiss a proposed derivative class action in Delaware stemming from the company's Cambridge Analytica scandal, arguing that the board ignored “warning flag after warning flag” that led to a massive breach of user data.

In a Chancery Court filing made public Monday, plaintiffs argued that deep conflicts on Facebook exposed the Facebook directors to serious liability for their role in allegedly hiding from users, investors—and the U.S. Congress—Facebook's practice of sharing private data with outside parties.

The 122-page document targeted company founder and CEO Mark Zuckerberg's dominance over the board and said the board was incapable of acting bringing past violations to light or preventing further damage in the future.

“The board had numerous warnings about these practices from regulatory actions, regulatory settlements, whistleblowers within Facebook, and media reports,” the filing said. “The illegal practices created a snowball of liability that logically culminated in the largest data breach in history and Facebook now faces enormous liability as a result.”

Zuckerberg and other Facebook directors moved to dismiss the suit in September, arguing that it was up to the board, not individual investors, to decide whether to pursue litigation in the wake of the Cambridge Analytica debacle. The lawsuit, they said, failed to implicate a majority of the board members and thus should be dismissed under the Chancery Court's Caremark theory of director liability, the toughest standard for corporate plaintiffs to meet.

This is a developing story.