According to The New York Times, SpaceX fired nine employees who grouped an open letter in the summer condemning CEO Elon Musk‘s online behavior.

According to the NYT, some SpaceX employees circulated a letter on June 15 urging the company to condemn the billionaire’s “harmful Twitter behavior.” The letter came in response to an Insider report in May about SpaceX settling a sexual harassment claim against Musk, about which he joked on Twitter.

According to Insider, SpaceX fired the organizers of the letter the day after it was published. The NYT reported that it was unclear how many employees had been fired, while Reuters reported that at least five employees had lost their jobs as a result of the letter, citing two sources.

According to the NYT, which cited workers and lawyers, nine SpaceX employees were fired as a result of the letter. According to the newspaper, charges alleging unfair labor practices were filed with the National Labor Relations Board on Wednesday, involving eight of the nine fired employees. According to the charges, it was illegal for SpaceX to fire the employees.

“Elon’s behavior in the public sphere is a frequent source of distraction and embarrassment for us, particularly in recent weeks,” employees wrote in the letter, which was obtained by the NYT in June. They urged SpaceX to “separate itself from Elon’s personal brand” and make clear that Musk’s messaging “does not reflect our work, our mission, or our values.”

According to two SpaceX employees, the company held a meeting for 20 engineers the day after the firings. According to the New York Times, SpaceX’s vice president, Jon Edwards, stated during the meeting that the employees behind the letter had been fired for criticizing Musk and distracting the company.

“SpaceX is Elon, and Elon is SpaceX,” Edwards said, according to two employees who spoke with the NYT.

The report comes as Musk has fired about two dozen Twitter employees for openly criticizing him on the social media platform.