this is RANSOMWARE trojan
It has NOTHING to do with any government department or countries' police !
It preys on your IP address, and modifies the screen pictures to suit the country codes.
FBI or CIA in the US. - and also State specific police logos have been seen.
Scotland Yard for the UK,
Gendarmeri Central for France .
Australian Federal Police in Australia ..., and so on
This is NOT specific to just USA!
READ the text don't skim the titles!
Your computer becomes completely LOCKED.
You can't do any recovery until the Virus is removed.
Look up UKASH Ransomware virus or Trojan .
These skumbags have got smart - they demand anything from $100 to over $200 [ or equivalant in which ever country currency ] to be sent to a UKASH link which can be cashed at any ATM which allows UKASH numbers - almost untraceable --- BUT you still do not get your computer unlocked, just thrown the money away, and possibly given your email and banking details to the crooks!