After receiving complaints that the esports team owner verbally abused and bullied current and former employees and esports players, Riot Games is investigating TeamSoloMid founder and CEO Andy Dinh for workplace misconduct.

Late last year, the West Los Angeles-based Riot began an investigation into Dinh’s behavior, as Wired first reported on Tuesday. Dinh’s TSM competes in Riot’s annual “League of Legends” World Championship tournament, one of the largest and most prestigious esports tournaments in the world.

Dinh, who goes by the name “Reginald” in the gaming community, founded TeamSoloMid in 2009. Dinh began his career as a professional gamer and served as captain of TSM for four years before moving into his current management position. TSM, based in Playa Vista, has since grown to become the world’s most valuable esports organization, according to Forbes, with a $410 million valuation and $45 million in annual revenue. Lenovo, Red Bull, Axe, and HTC are among the team’s major corporate sponsors.

But, according to reports, Dinh has been under investigation by both Riot Games and TSM for abusive workplace conduct since November, shortly after former TSM player Yiliang “Doublelift” Peng called him out on a Twitch live stream.

To Wired, a number of current and former TSM employees expressed similar concerns about Dinh’s “mental abuse.” Dinh would tell people their work was “trash,” according to one current employee, who spoke on the condition of anonymity. He also recalled a time when Dinh made someone at the company cry at least every other week. Dinh’s wrath, according to another former TSM employee, sometimes extended to his esports pros, who were also reportedly reduced to tears.

Dinh was fined $5,000 by Riot in March after making derogatory comments about a player on rival esports team Cloud9 during a live stream. Dinh later apologized, saying his remarks were “overboard.”

According to Wired, more than a dozen people complained to the North American Players Association about Dinh’s behavior, and the esports players’ organization forwarded the complaints to Riot Games.

TSM said in a statement that it is “taking the allegations very seriously,” and Dinh also issued an emailed statement in response to the allegations. While denying specific allegations, Dinh stated that he has “zero tolerance for underperformance.”