Activision Blizzard employees and the Communications Workers of America (CWA), a major media labor union, have filed an unfair labor practice lawsuit against Activision Blizzard accusing the video game company of worker intimidation and union busting. The union claims that Activision Blizzard is using coercive tactics to stop employees from unionizing.

The lawsuit is one of several against Activision Blizzard, which was previously investigated by California’s Department of Fair Employment and Housing (DFEH) over claims of widespread sexual harassment and gender-based discrimination. The DFEH sued Activision Blizzard in July, alleging the company had a “frat boy culture” that included gender-based discrimination and harassment. It was followed by a class-action suit from shareholders in August that claimed the company had violated federal securities laws.

In a statement shared with The Washington Post, CWA organizing director Tom Smith said: “Management could have responded with humility and a willingness to take necessary steps to address the horrid conditions some [Activision Blizzard] workers have faced. Instead Activision Blizzard’s response to righteous worker activity was surveillance, intimidation and hiring notorious union busters.”

The employees and the CWA union filed this most recent lawsuit in California with the National Labor Relations Board, alleging that Activision Blizzard acted coercively to stop unionization using tactics such as surveilling employees, interrogating them, making threats and promising benefits.

Following the suit from the DFEH, Activision Blizzard hired law firm WilmerHale to conduct a third-party audit. Shareholders have criticized that as a poor choice, noting the firm’s reputation for defending wealthy clients and lack of a track record in uncovering wrongdoing.

Activision Blizzard is not unionized. In a late July rally attended by more than 350 people, employees staged a walkout to protest the company’s reactions to being accused of sexual harassment and discrimination. Blizzard employees also banded together to form A Better ABK, a group that advocates for workers’ interests. The action was later mirrored by workers for the gaming company Ubisoft, who created A Better Ubisoft.

Activision Blizzard is one of the world’s biggest gaming companies, with 9,500 employees worldwide, a market capitalization of more than $60 billion and hit franchises like Call of Duty and World of Warcraft. One of its largest subsidiaries, Blizzard Entertainment, founded in 1991, was named extensively in the DFEH lawsuit.

Activision Blizzard, the CWA and lawyers for the case did not immediately return requests for comment.

Elsewhere in the company on Tuesday, Activision Blizzard announced it hired two new senior executives: Julie Hodges, a human resources executive from Disney, as chief people officer and Sandeep Dube, former revenue management executive at Delta Air Lines, as chief commercial officer.