[Reread the crimes. The Jelkef brothers committed many crimes that merit True Death. Vileneck did not commit one. No killing he did ended in True Death. He did not use poisons or magics that would end a person's life in truth Death. He did not plot to overthrow the government. His crimes were thief, assault and killing (not the same as murder, as the people came back), etc. His max sentence would have been life in prison (two weeks for him). Without the staff, he is as weak as an old man, and could not wrestle a child and win. His body was destroyed by the warped power of the staff and the fight with the guards. Banishing him was a far worse punishment than imprisoning him, as his life might have been extended with care in the prison. They basically cast him to the wolves. It was the audience that was not listening. As for the reason for the arrests, that was not the time or place to bring up points or new evidence, as mentioned in another thread. The public was there to witness the sentence, not be jury. The sisters were interviewed later, one was banished for a week for her involvement with the Night Rogue's plot, and further knowledge was added to the
investigations still going on to find the possible mastermind behind the plots. As with keeping the plan to capture the rogue secret, perhaps it would have been very bad for the sisters to say where the last staff might be in pubic, so as to tip any spies off to an
ongoing investigation. The guards are not inept, they are just drawn that way.

My advice is to have your characters look at the events a little closer, rather than getting outraged at what is seen on the surface.]
[edit to below: Understood. The above comment was also not about the player getting outraged, but the character, just to clearify. (and to give folks a little hint on what is really going on). Carry on.]