Dagmar is not, of course, excluded from this whisper, but his hand is held to direct the voice - and handily, to block any lip reading attempts.
"It was left as a sign to be found afterwards, by the attempted assassin." A bit of disdain, after all, she failed.
"But." He says, with emphasis, "I think it is a plant. A red herring. It was too obvious. The Blade gets the blame, an alliance broken, and assassin gets paid... and chaos reigns."