I think to answer those questions, I would need more information. If I tried to answer them it would only be speculation. Which generally is what most people do when they give their opinions. Perhaps though that there was leaked classified information from several individuals. Maybe this girl was one of them and they caught her. Maybe she knows more information that she hasn't released and they are keeping her incarcerated for that reason. Maybe they want to make an example of her to other leakers in the future. I know she didn't get released on bond. From what I read they believed that she posed a flight risk and also could be risk to talking to the press.
Here is some crazy thoughts. We are a nation of laws. There are federal, state and local laws. Laws are not partisan. We may not like particular laws but as citizens we must obey the laws. Not following/breaking the laws, by definition, is, well, illegal. Now whether the law enforcement group (department, agency, etc) charges you with a law or may depend on circumstances (e.g. an officer letting you off with a warning for speeding, lack of evidence, some judge who doesn't feel they actually uphold laws-be it mercy or otherwise or others). To willfully not enforce laws is anarchy. Oh hey, guess what, there are all kinds of laws...around life, theft, privacy, immigration and many many others. I believe when local and state officials willfully fail to enforce laws it's a problem... If we take partisan politics out of the discussion...and even the media noise. It boils down to this...somebody broke federal laws at least around handling of classified information. There is apparently adequate evidence (already) to hold her and presumably charge her for something. As part of the process, the legal system will consider the evidence and circumstances from their investigation and try to make a case she committed one or numerous crimes. She will be charged or aquitted. If charged it used to be as simple as this 'Ya do the crime and ya do the time'.