Well, there is another part of a lawyers job. Since they also influence the judges. If the person they're representing is guilty and will be found guilty, sometimes the thing they're trying to do is make sure the right punishment is assigned.
Not all murders get the same charges. Sometimes people kill in self defense, sometimes accidents, something forces them, things like that that deserve less punishments than someone who planned and executed a murder in cold blood. Intentions can mean a lot at times.
So it's important for lawyers to know what type of person they're defending is. So...I think if he's a good lawyer, he'll see that despite what Corvus has done, they're not bad people because of it.
Besides, prison is all about rehabilitating people. Lawyers should believe in second chances.