Guilty men tend to freeze and then do the next wrong thing.

Here at the end of Genesis 42 (18 to the end), we see Joseph's brothers knowing they are guilty of their brother's blood (Joseph) try to act all honest (we find out later that they answered questions because they were asked directly of them, so they did not offer up info freely, and as they depart and find they still have their money, their first response is not to return it, but to think they are in more trouble.  Their father, when they return, fails to act as well.  Lesson, inaction is not a right action.