Can an IP address be traced? I am being threatened?

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ok so a few days ago someone made a fake facebook account of me for the second time in a year. The first time they just edited pictures of me and put makeup on my face. (I am a man). I filed a police report but didnt think too much about it. This time they made it under my name and they are talking about my brothers wife (I dont talk to my brother and she is the reason why) and saying that she is dead even though she is not so I filed another police report. Now her family members who think I made the account are threatening me (they are not in America while I am). I reported the account 3 or 4 times on facebook and they have still not replied. I sent them emails telling them I would get a notarized statement and whatever else they wanted but I just want to know who did it. I also emailed the Chief of police in my area and he replied once telling me he was sorry and asking for the police report number. I gave him it 2 days ago and he didnt reply since. I sent him another email this morning and he still did not reply. What else can I do? Do you think they will eventually tell me who made the account? Thanks