Government system or stealing information
The Police can but the FBI Only does cases about Government system or Stealing personal information
Actually "Hacking" (or really "cracking") online accounts is generally impossible unless the user has a weak password like just a name.
Other than that, fraudsters steal logins & password by "social engineering" – phishing scams with emails that try to get people to enter all their info into a fake look-alike web page.
That is *not* hacking facebook / ebay / paypal / your bank etc., that's just the 21st century version of confidence tricksters & scam artists – con men..
In other words, YOU either used a stupidly weak password or YOU typed your password in to a fake web site after being taken in by a trick email.
(One of the most fundamental rules of internet/computer security is _never_ click anything in an email, unless you explicitly asked for that specific email to be sent to you).
That's why the FBI / Police etc. are not interested in your case – they want the people that set up the scams and fake emails & they have millions of examples of those to go at.
They also work with other international agencies – and they do catch the people / gangs involved.
They have way more important things to do then to concern themselves over your " little " facebook account….
So change your password…..do not store your password on your computer….do not give out your password…make your facebook password unique to facebook …( a lot of people use the same password over and over for all the places they go to )
local police handle that.
FBI only deals with cases crossing borders.
next time, choose a stronger password…