The American chess grandmaster at the centre of the sport's biggest scandal has been accused of cheating more than 100 times on a major online platform.
Hans Niemann, 19, has been the talk of the chess world after five-time world champion Magnus Carlsen accused him of cheating during their Sinquefield Cup game in September.
Niemann denied he cheated and even offered to play naked to prove he was clean, but did admit to cheating twice in his life, aged 12 and 16.
However, major website Chess.com has released a 72-page report that highlights more than 100 games where the platform believes Niemann cheated.
The games are dated between July 2015 and August 2020.
The majority of the alleged cheating offences happened in games in 2020, when chess gained a surge of popularity online as the world dealt with the COVID-19 pandemic.
"We present evidence in this report that Hans likely cheated online much more than his public statements suggest," the report states.
"Consistent with the letter we sent Hans privately on September 8, 2022, we are prepared to show within this report that he, in fact, appears to have cheated against multiple opponents in Chess.com prize events, Speed Chess Championship Qualifiers and the PRO Chess League.
"We also have evidence that he appears to have cheated in sets of rated games on Chess.com against highly rated, well-known figures in the chess community, some of which he streamed online.
"These findings contradict Hans' public statements."
Carlsen withdrew from the Sinquefield Cup in early September after losing to Niemann who was playing with the black pieces.
The world champion did not make an official accusation of cheating until the end of the month, but a cryptic social media post alluded to him believing there was foul play in that game.
Niemann categorically denied that he cheated in the Sinquefield Cup, which was played over-the-board and not online.
Chess.com in its report said it had no evidence that Niemann had ever cheated over-the-board or in his game against Carlsen.
However, the report said Chess.com found aspects of the Sinquefield Cup game "suspicious".
The website did remove the American teenager from its Global Chess Championship in the fallout from the Sinquefield Cup, information made public by Niemann himself.
The website said it did not want its cheating concerns with Niemann to be publicly discussed, but it had no choice after the revelation by the teenager.
Chess.com in its report has also posted an online conversation between Niemann and Chess.com administrators, discussing some of his cheating bans.
The 2020 conversation between Niemann and Daniel Rensch — an international master and chief commercial officer of Chess.com — shows Niemann apologising for cheating and promising not to do it again once his ban was lifted.
The report states Niemann also admitted to cheating in a phone conversation between the two.
Chess.com has said it has no evidence to suggest Niemann had cheated since 2020, after his ban was lifted.
"Our investigation has revealed that while there has been some noteworthy online play that has caught our attention as suspicious since August 2020, we are unaware of any evidence that Hans has engaged in online cheating since then," the report said.
"Our investigation has concluded that he did, however, cheat much more than he has publicly admitted to, including in many prize events, at least 25 streamed games, and 100+ rated games on Chess.com, as recently as when he was 17 years old."
Niemann has not commented on the report.
