James's clues aren't always very trustworthy, we wouldn't recommend relying on them alone to find the assassin since they might and might not point you to the correct group. Imprisoning/protecting someone apply only to the assassin's actions that night (e.g. imprisoning the assassin means they won't murder anyone that night, although the assassin might not murder anyone even if left alone), the daily alibis don't currently tie into that. However, we see how that might be confusing since the Prince specifically asks about the last night, we'll try to make it more clear. Thanks a lot for the feedback! -M