story
(https://en.chessbase.com/post/is-hans-niemann-cheating-world...)
The counter to that is that it looks likely that a clever high-level player could probably use an engine once or twice in a game in a judicious way and not raise statistical alarm bells. But still, Ken's work tries to suss out things like that--e.g. does the player in question make good moves in 'key' positions. Plus, continued use of such techniques over time would leave a statistical trail.
Honestly, Magnus' statement of, "well, he beat me and it didn't look like he was thinking hard" is pretty thin. Magnus knows that Hans has a history of cheating in online games when he was younger and to me it feels like he's just seeing ghosts and deep into confirmation bias territory. Especially since the game in question took place at a high-level tournament with rigorous anti-cheating scanning, etc.