How to delete FAKE account?

Hello,

I had problem that there is someone make a Facebook account that pretending as my father Facebook account. Both Facebook is really same just the profile name he/she make little bit different. That Facebook is really disturbed because he/she post something that useless and make my father's reputation become bad. I had done with report function that got in Facebook but still that account is active. I do not know how to close that account. Please anyone know how to delete that fake Facebook account?