The crowd was stunned by Dyon's words…
However, were his deductions really refutable? The movements of the Sigebryht family hadn't made any sense.
Why would Zaltarish do something like burn down an orphanage and fill it with feces knowing the fact that Grand Elder Cormyth was not an unconditional supporter? It was clear to everyone that the fact Cormyth supported a member of the Grimbold family in inheriting the headmaster position of Mathilde Academy, that he was not all in on the Sigebryht family.
And… if you dismiss it as an act of pure rage instead of one of strategy, then why would he only kill a poor old nanny? Wouldn't it hurt Dyon more if all of the kids died as well?
Then there was Aeson, why was his death necessary? Not only was the timing odd because it put Dyon directly into the line of questioning… Aeson's death, no matter how callused it may sound, meant practically nothing.