How do I trace someone who has hacked my facebook?

[Darren]

I have had my facebook account hacked by someone and now I am receiving letters from them at home and at work. Is there a way of finding out where this person has signed in from on facebook or a number I can call to find out? How could I trace this person?
please dont reply "you can" please offer some details how I can...

[R]

You can but it costs a lot of money.

[sewrobb]

That information is only available from FB.

http://www.facebook.com/help/?ref=pf#!/h...968648557/

[UD]

http://webapps.stackexchange.com/questio...last-login
Write down the IP that you suspect and terminate if it's still active. Then report the IP to the Facebook, by email or report link.
If you want to check your computer's IP, just in case, go to start menu then type "cmd" on the search box and press enter. Then you'll get a window called "Command Prompt", and type on that window "ipconfig"(if this shows error then put space between "ip" and "config") and you'll see the IP address. Don't forget to terminate suspect session from Facebook.
Good luck!