The National Labor Relations Board will investigate Barstool Sports founder David Portnoy’s tweets claiming he would fire employees “on the spot” if they contacted a reporter to talk about unionization.

According to The Hollywood Reporter, a group called the Committee to Preserve the Religious Right to Organize filed charging papers with the NLRB claiming Portnoy was “crazed” and had “threatened to discipline employees on account on Union and/or protected activity” in his tweet. “The Charging Party seeks as relief that Mr. Portnoy be required to tweet and otherwise publicize his severe and sincere apology and to post the appropriate Notice on the public website,” read the filed charges.

The agency has reportedly acknowledged the filing, and sent a letter to Barstool Sports for its response. NLRB agents will then reportedly gather evidence and take affidavits from involved parties and other witnesses. Rep. Alexandria Ocasio-Cortez (D-NY) got involved in the outrage earlier this week and blasted Portnoy’s tweet was “likely breaking the law.”