My question involves criminal law for the state of: Ohio
I am in desperate need of legal advice regarding my younger sister and her criminal boyfriend. My younger sister is in a relationship with a man 9 years her senior (She's 21, he is almost 30) who went to jail for 9 years for armed robbery and started dating my sister soon after he was released. He got her pregnant at 19, and again at 21 (she is pregnant now with her second child). Within a year of being released he has violated his probation and was wanted in 4 cities in the area.
A bit of very relevant background information: Last March (2012), I got a call from her best friend that he had beat her the night before and she sent me picture evidence. I immediately called my mother, who anonymously called the police soon after. My sister lied to but the police, but they pressed charges anyways. He ended up being fined, and never paid his court fees.
In August, my mother got a call from the police that they were going to break down the door of the condo she owns (that he and my sister live in) if he did not open the door. He was arrested and brought to jail, where he was charged with stealing a girl's computer, identity theft, unpaid fines and breaking of his parole. He is currently in jail for 10 (?) months by the recommendation of his parole officer. She was charged with harboring a fugitive, which the police brought down to a misdemeanor and ordered a no-contact order by the court.
My sister still contacts him and visits him in jail regardless of the order. He cheats on her and has laid his hands on her twice. I guess my question is: what can I do about it? Can I call his parole officer or the police, and why do they let her visit him in jail? I have her phone records that show him calling her and sending her letters from jail.
I am terrified for my nephew and soon-to-be niece that he will harm them and my sister again. He is a belligerent drunk, uses drugs in front of his son (and in general) and just a terrible person. I love my sister, but I am willing to face the consequences in order to keep her children safe. Is there anything at all that I can do?

