I was cyberbullied by a fake account?

[Hey]

So a fake account left me a very cold-hearted and long message on my facebook account. I have narrowed down their true identity to three people but I can't be sure. I want to find out who it was. I'm not going to tell them that it's them that I know it's them, I just want to find out for myself. How can I?

Don't tell me to just ignore it. I will, but I want to know who it is too.
It was a very lengthy message...it was very rude, and lots of swearing.

[Fireball]

REPORT TO THE OWNERS OR JUST GIVE UP ON F8CEBOOK...NO PRIVACY...EMAILS AND PHONES ARE MUCH BETTER..

[Tyvern]

It couldn't have been any worse than "hay beyotch go kill urself ur ugly."

[Ronald Cunningham]

Welcome to the Interwebs.

[Bubba]

sorry don't really care

[Kittysue]

You have to report this to the police. Cyberbullying is now a crime in many jurisdictions. You have no way to find out who did it. You have to file a police report, and if they think a crime has been committed then they need to get a court order to subpoena Facebook's records to find out who made the post in order to file charges
You have no access to this information - only law enforcement can find out who posted it
Print out the message and go to your local police

[Victor]

Keep in mind it depends on how public your drama is..You said it was possibly one of a few people, there are trolls who also thrive on stirring up drama who are sideline watchers; Your best bet is to truly let it go unless you wish to enter the world of hacking, and that is a game I dissuade anyone from becoming.

[Alexander]

that's cyber assault and battery report it to the authorites.