The National Labor Relations Board has filed a complaint against Google, accusing the search giant of monitoring employees and firing them without just cause.

According to Reuters, Google is accused of monitoring and questioning employees that were attempting to form a union and were critical of the company’s efforts to discourage such activities. The employees were placed on administrative leave and ultimately fired.

Google claims the employees breached the company’s policies, and accessed information they were not authorized to. As CNETreports, however, the employees say they didn’t break any rules by accessing the information in question.

What’s more, the NLRB has found that Google acted unlawfully, both in placing the employees on leave and firing them, as well as in their efforts to investigate the employees, since the efforts were based on deterring unionization.

Google has increasingly been under fire from its own employees for a wide range of issues, including working with China, taking on military contracts and generally backtracking on its original motto of “don’t be evil.”

Google has until December 16 to respond, after which the case will go before an administrative law judge on April 12.