Alireza, Ian, Magnus, Fabi, Wesley, and Levon have since made statements that imply they believe Hans cheated, or at least that they were suspicious of his play, as well as Yasser and Hikaru.
That's the majority of the players in the Sinquefield cup. Even Levon, who was initially skeptical, has since reversed his position.
As is tradition in chess, no one says "He cheated" they say things like "his moves were better than one would have expected" or "superhuman" or "I felt like I should trust my opponent over my calculation".