using fake id

I have come across a facebook profile of a girl which is fake and is handled by a man since many years. The person uses the girl's profile to send illicit messages to other girls. as far as I could figure out he does this to find details about other girls and get close to them. All this is happening since many years. This is a crime. I could not trace the girl because I do not know her. But I wish to tell her about the crime which she is perhaps not even awared of. What can I do about it? Being a girl I can not turn a blind eye towards it.