What to do when my children's father has bad history?

Dear reader,

I have been having problems with my childrens father. I had an original question that explains most of it. Original question/situation:

I am worried about the safety of my kids concerning their father. We are not together because of our abusive relationship and I am worried that he might try to hurt our children after the court says he is okay to be around. At the moment he can’t have any contact with me or my kids but it’s only a matter of time before the court will let him go near us. Even with supervised visits I mean how long do those last, I’ve never heard of a 16yr old having a supervised visit. My kids are 3months and 2yrs. I have been taking him to court because he beat me and tried to kill me while I was pregnant. The police said it was a domestic case and because I defended myself from him killing me that we both should get arrested. If I when it happened there’s a good chance I wouldn’t be here typing this message and that my children wouldn’t be here either. Anyways before I had met him he was with another woman, they dated for a year in a different state/province she also lives there. They had a daughter together but something happened between them because they are not together, he has no rights to his daughter, his daughter doesn’t have his last name, and I have never met either of them. When we were dating he hid this from me and I found out through his friends that I don’t talk to any more. I don’t know to much about his background and anything he ever told me was a lie or not the whole truth. How can I find out if he has done something terrible in some other part of the world? like a complete criminal background check containing any kind of assaults, restrain orders, felonies, sex assaults, any kind off jail time. When we had our last court the lawyer I had said he couldn’t get his info because it was out of state. I’m here thinking what if he went to jail for stabbing some one, or beat the heck out of his daughters mother, or is in a gang. That isn’t some one I would ever want my kids be around for safety reasons. My feelings are strongly suggesting that something isn’t right, mothers intuition. Is there any way of finding this kind of information out? My question now:

I recently spent about $80 on a national background check (I think this is what it was called) It allowed me to see any criminal records he has and any records his family members have. I was in shock! He has attempted murder charges, charges as in more than one, several cases involving drug trafficking heroin and opium, endangerment to a minor, the list went on and on. Also this all happened out side the state that I lived in. This was all hidden from me just like him having a daughter. I am terrified for my children after finding this out, if anything were to ever happen to them I don’t know what I would do. I do not want my children to ever go anywhere near him after finding this out. Has any one any suggestions for me? I realized I didn’t know anything about him when I was involved with him. My friends and family are not being of any help to my situation, all they’re doing is making me feel awful. If no one has experienced this situation has any one ever seen court cases with it on T.V. or know some one that was in my situation? What was the out come? What should I do? PLEASE I REALLY COULD USE SOME ADVISE!