The International Chess Federation (FIDE) announced Tuesday that it has filed a formal complaint against former World Chess Champion Vladimir Kramnik over unproven allegations of cheating against fellow players, including the late American grandmaster Daniel Naroditsky.

The complaint centers on harassment and “the insulting of an individual’s dignity,” according to a FIDE news release. Naroditsky, who died last month at age 29, was among the players Kramnik publicly accused of cheating, accusations he continued to share on social media. The cause of Naroditsky’s death has not been disclosed.

A rising star in the chess community, Naroditsky helped popularize the game online through educational videos and livestreams. In his final livestream before his death, he reflected on the impact of Kramnik’s accusations:

“Ever since the Kramnik stuff, I feel like if I start doing well, people assume the worst of intentions. The issue is just the lingering effect of it,” Naroditsky said.

Several other grandmasters, including Hikaru Nakamura and Nihal Sarin, criticized Kramnik for harassing Naroditsky. Kramnik, contacted via his GoFundMe page, did not respond to requests for comment but has previously described FIDE’s investigation as “insulting and unfair.”

The FIDE Ethics & Disciplinary Commission’s complaint outlines what it calls a “pattern of conduct over roughly two years” involving possible harassment. Testimony includes statements from Czech grandmaster David Navara, who Kramnik also accused of cheating, and associates of Naroditsky.

FIDE rules allow sanctions against players who make unsubstantiated accusations based on emotion or insufficient evidence and require solid proof to initiate cheating investigations. There are no records of FIDE ever investigating Naroditsky.

Tuesday’s announcement marks the formal filing of the complaint, following the federation’s prior referral of Kramnik’s statements to its ethics commission.