The North American branch of the Japanese video game maker Nintendo has been accused of violating a worker’s legal right to form a union in a complaint to the National Labor Relations Board. An unnamed worker filed the charge against Redmond-headquartered Nintendo of America and recruiting firm Aston Carter last Friday.

On Monday, Nintendo and Aston Carter received a letter from the NLRB with a copy of the complaint, stating that the companies would be investigated. The investigation process takes several weeks.

Both companies were accused of discharging an employee within the last six months for joining or supporting a union and engaging in protected labor activities, which include discussing wages or terms of employment. They were also said to have surveilled employees, according to the complaint. The complaint was redacted to hide the employee’s name.

Nintendo of America is the video game giant’s North American branch. Aston Carter- – a far less prominent player in the video game industry — has posted job listings for Nintendo contractors and service representatives in the past. Nintendo and Aston Carter did not respond to comment.

Under the National Labor Relations Act of 1935, workers have the right to organize and form collective-bargaining units to discuss wages and terms of employment.

Nintendo isn’t the only gaming company being investigated by the NLRB over union-busting allegations. Activision Blizzard, the company behind games like Call of Duty and World of Warcraft that Microsoft is attempting to purchase, faces multiple complaints for preventing employee union activity and surveilling and threatening employees. The NLRB is now weighing in on a labor dispute between the employer and employees at Raven Software, a subsidiary of Activision. A decision is expected within the next few weeks.