help finding information on a stalker?

A very good friend of mine is being harassed by a woman who is sending her letters, emails, and messages via MySpace. My friend lost her husband over in Iraq over a year and a half ago. My friend is now in a relationship and this person is telling her what a horrible person she is for being in a new relationship. First of all it's none of this persons business and how dare she attack another person who has had to endure the worst of being an Army wife. What I need to know is if I can find out her name using the email address she used to send the emails from. It is a gmail address. I also need to know if there is a way to get into a private myspace acct. This woman has to be stopped and the police cannot do anything about it until we figure out who she is. Any help is appreciated.