A new shareholder lawsuit has accused the Tesla board of engaging in a conspiracy to cover up its failure to monitor CEO Elon Musk's “increasingly erratic” public statements, in a case that could set up the question of whether Musk's tweets qualify as company statements.

The derivative complaint, filed Thursday in Delaware federal court, is the latest to target Musk and the Tesla directors over a series of missteps from the outspoken executive, including a tweet in which Musk said that he had “funding secured” to take the Palo Alto, California-based carmaker private at $420 per share.

In a 64-page complaint, plaintiff Ross Weintraub said the board had “completely abdicated” its duty to oversee Musk's public social-media posts in an attempt to protect their own positions with the company.