It appears, tpcslj47, that your question was mostly answered on the other site and that, by contacting Facebook, your friend has already followed at least some of the advice offered.
What was not addressed on the other site was invasion of privacy and, for that, an answer to Proserpina's question would have been helpful (which is why Proserpina inquired a couple of times of you about the damages suffered by your friend).
As you have already been informed through your research, hacking is illegal, and copying another's written expressions without permission could be considered infringement.
The hacking is handled by filing a complaint with the police and/or with the local FBI field office. It is relatively easy for someone to hack into a computer (as evidenced by the hacking of Sarah Palin and John McCain's email accounts and the hacking of Bill O'Reilly's website). While hacking can be charged as a felony under state laws, a hacker must first be identified, caught, and (generally) be in the same state as the "hackee," unless jurisdiction over the hacker can be established in the hackee's home state.
The infringement of copyrights, the copyrights of which would be held in the writings of private messages that were communicated and then republished without consent, can be handled through the filing of a DMCA take-down notice. You can google "Digital Millennium Copyright Act" for information on how to file a complaint or go to the U.S. Copyright Office's official website at
http://www.copyright.gov.
If what was published about your friend can be seen as highly offensive or sensitive in nature to a "reasonable" person, and the information is of no public interest or concern, your friend could additionally seek out the advice of an attorney in her area about an invasion of privacy/publication of private facts civil tort action. Although invasion of privacy is also covered under state
criminal laws, there are specific elements involved with criminal invasion of privacy that do not seem to be present here (although a review of what exactly was published about your friend would be needed to determine this).
Whether a civil invasion of privacy action filed against the hacker would be worth the time and
high expense of pursuing would be contingent on all of the facts and largely determined by the extent of economic and/or reputational injury (damages) suffered by your friend that can be directly attributed to the publication online of the private information (which, again, goes to the question asked of you by Proserpina).
Then there can also be problems establishing liability in an invasion of privacy/publication of private facts. Liability is often demonstrated by how private these facts actually are, in addition to how these facts were obtained.
Your friend first of all made a common error. She assumed, wrongly, that private information communicated in
any form on the internet will remain private. The ONLY way to ensure private facts remain private is to not communicate them to others at all. Then, if communicating these facts are, for some reason, necessary, they should be communicated through either secured channels or with an express agreement with the person receiving the information that the information will remain confidential. Once communicated, there is never a guarantee that the information will remain private. Your friend essentially made the private facts "public" by revealing these private facts to another.
Your friend may wish to consult with an attorney in Nevada. The attorney can review exactly what was published and can review all of the facts of the matter and can give your friend a better idea of whether pursuing a civil action against a person located in Oregon would be worth it. This would not be an inexpensive pursuit, by the way - think multi-thousands of dollars. The damages suffered by your friend (again, a response to Proserpina's question would have been helpful

) will help your friend determine whether it is worth these costs.