There is Niemann's Sept. 6 admission after Round 5 of the Sinquefield Cup that he cheated online at ages 12 and 16.
The rest is "likely cheated," "appears to have cheated," and "suspect games". No evidence whatever of cheating over the board at any time has been alleged. It was alleged that he "likely" cheated online up to 42 days after his 17th birthday. No allegation of cheating as an adult was alleged.
Please note that there is NO discussion of his OTB classic games in this report. Report at 3: "Despite the public speculation on these questions, in our view, there is no direct evidence that proves Hans cheated at the September 4, 2022 game with Magnus, or proves that he has cheated in other OTB games in the past."
Report at 19-20: "Chess.com is unaware of any concrete evidence proving that Hans is cheating over the board or has ever cheated over the board."
The suspicions of Chess.com about Neimann’s cheating in online games (which also raise his ELO score) have to do with the use of multiple monitors while playing the games.
No issues with the use of multiple monitors - many GMs routinely play simultaneous games.
But they stated that his head movements checking other monitors coincided with the playing of the “best move”, which is where they came up with the suspicion.
No concrete suspicions since they were not videotaping his online setup, but it fit the pattern of their cheat detection algorithms.
Neimann may be clean as the driven snow but enough GMs feel that he is playing outside of the boundaries of chess, to make them feel uncomfortable.
Which they do not sense from any of the new young GMs from India, for instance.
Several days later after returning to Norway, Magnus shared in a private conversation that his experience in playing Hans was “unlike a game he’s ever had.” He emphasized that he has competed against numerous prodigies and players who “exert” themselves and show great effort throughout a long, difficult fight like this game. He described Hans’ level of exertion as “effortless” and felt he never had a chance to get back in the game, which was extremely unusual for Magnus who is known for his resourcefulness. Hans’ lack of emotion or excitement about the result was also noted by several others.
It is hard to understate the respect that the chess world has for Magnus, which has been earned over the last decade. The report notes compares the emotion for five players that have beaten Magnus, including Hans. His emotional response is not like the other players ...
Chess.com is set up to catch online cheaters, especially in speed chess. They readily admit that they do not police OTB games, since they are not the organizers of these tournaments. In this case they did apply the same anti-cheating rules that they use in other online games, and found suspicious activity.