Cassius had a suspicion.
However, this thought remained his suspicion for only a couple of days.
A few days ago, when he received the news about Neirin Halstead's passing, he was one of the people besides Vincent who did not accept such news. After receiving the news from Rowan, Neirin's personal guard and the person who found Vincent with Rezef and Anna, Cassius prioritizes the events that happened in that laboratory more than rehabilitating the empire.
In those few days, several people had undergone questioning, and he, himself, led the investigation.
According to the survivors of the academy, they didn't see the duchess among those who were hostage and were surprised and shocked by the fact that she was at the scene. The presence of the young master Vincent was only confirmed after a few hours of the event.
