Set Outlook to recieve Facebook messages.Once she recieves an abuse message,take a look at the message headers.They provide a LOT of useful informations that can be used to track anyone down.
So just copy all those headers into let's say NOTEPAD,save that as a simple text file and send it to me on the following E-mail address:
[email protected]
After that I am going to send that file to the police and tell them to try track that down.If her sister in her town already has the police who is doing this things then tell her to send that text file to them.If not,you send it to me and I will forward it to the police.
This is not the first case of something like this happening.There was one case where many people on facebook were psychicaly torturing one girl and they were doing that so much ALL THE TIME for a long time that at the end poor girl couldn't take that anymore and she killed her self.
There are many crazy people on facebook who are dangerous and they should be tracked down as soon as possible.So tell your sister to do what I told you as soon as possible.If she has a police in her town who does these things then let her know to do what I told you and that she sends that file to them.If not then send it to me on the E-mail address I gave you above and I will forward it to them.