Twitter Inc faces another lawsuit that claimed it illegally laid off contract workers without notice after Elon Musk bought the company last year. The suit was brought on behalf of an unspecified number of workers hired by Twitter through a Maryland based employee staffing company TEKsystems Inc. The shadow employees argued they were a “contingent workforce” with the same duties as employees and shouldn’t have been laid off without notice when Elon Musk took over the company.

“The employees Twitter paid through TEKsystems were not temporary employees,” according to the suit. Instead, they were routinely told they would have the opportunity to become direct Twitter employees, and “are part of the same mass layoffs affecting employees directly employed by Twitter,” according to the complaint filed in San Francisco federal court Tuesday. According to the complaint, the contract based employees weren’t given 60 days advance written notice when they were terminated, as required under federal and California law.

Twitter and Maryland-based TEKsystems, named as a defendant in the lawsuit, did not immediately respond to requests for comment.

Twitter laid off roughly 3,700 employees, or half its workforce, in early November in a cost-cutting measure by Musk, who paid $44 billion to acquire the social media platform.