There are books on the legal system. There are defense attorneys, prosecutors, and trials, although there is no jury and the judge makes the final call. Unfortunately for our dear prisoners, some people have absolute authority to sentence people without trial and Ambrose is one of those people.

The best bet for freeing the prisoners in that route is to make a case for their release to Ambrose or another high-ranking NPC that will be introduced soon after game opening. There will be a few other ways to get the prisoners out that will be revealed soon after as well.