Internet Crime Complaint Center ransom ware does exist. It is for real and available for complaints.
It demands a fine to be paid with UKASH or Money Pak, claiming that failure to do so would initiate a crime case against you.
Generally speaking, FBI Cybercrime Division is a rip-off that you shouldn't trust it at all.
FBI ANTIPIRACY WARNING virus is a brand new scam that's been spreading around the Web recently under the name of The FBI Federal Bureau Investigation.