SpaceX CEO Elon Musk’s tweets are once again being used in as evidence in a case filed with federal regulators. This time, the parties citing his tweets are former SpaceX employees, who are claiming that the company fired them in retaliation for circulating an open letter criticizing Musk’s behavior and his tweets.

Earlier this week, eight former SpaceX employees filed unfair labor practice charges against the company with the National Labor Relations Board. The ex-employees were involved in sending an open letter to SpaceX’s executive team back in June that criticized Musk’s behavior in the wake of sexual harassment allegations, which the SpaceX CEO denied. They also said that his posts on Twitter were problematic and that they did not reflect their work, mission, or values.

Why all the hubbub over Musk’s tweets, you ask? According to the open letter written by the fired SpaceX employees, “every tweet that Elon sends is a de facto public statement by the company.” They pointed out that Musk’s Twitter is routinely used to announce company news. Furthermore, in a surprise revelation, the employees stated that Musk’s Twitter account is referenced in the SpaceX employee manual as a source of company news.

Gizmodo obtained a copy of the complaint submitted to the NLRB from former SpaceX employee Paige Holland-Thielen. The complaint included the employees’ open letter as well as a list of more than two dozen tweets from Musk they claimed were examples of him targeting individuals, engaging in “subtle” sexual harassment, overt sexual harassment, bullying of individuals and marginalized groups, and excessive vulgarity inappropriate for their workplace.

“The content that Elon creates and promotes demonstrates tolerance, and even encouragement, of a workplace culture that is hostile to various marginalized and underrepresented groups,” the employees wrote in an addendum about Musk’s tweets. “By staying silent on his public actions, taken on a platform which is considered official company communication, SpaceX and its executives have affirmed that Elon’s behavior is acceptable at our company.”

As a result of their letter, the former employees say that SpaceX fired them, which they argue was illegal because they were engaging in a “concerted activity” protected under federal law. They also allege that SpaceX carried out a months-long “campaign of retaliation and intimidation” with dozens of employees to identify anyone else linked to the open letter.

Click through to check out the 25 tweets the former SpaceX employees included in their open letter to the company’s leadership team. For anyone who follows Musk closely, the content will come as no surprise.