Eldest Daughters Boyfriend and Family

Well I found out that my eldest daughter is see a new guy and no one told me and at first I tought he was ok but there was something wrong. I felt I wasn't being given the whole story. I took them out fro some wings at the Wing House in our town and watched a local baseball team play. I then called my EX-wife and asked her is there anything she would like to tell me about this boyfriend. Angela said that apparently this guy has been arrested for molesting a girl younger than 16 y/o and she has been having sex with him for a month after dating him for 1 1/2 months. I said what?. Well now I know why the hairs stood up when I looked at him. I decided to have a meeting at my apartment with the 2 of them and asked Angela if she would like to attend and she accepted. I did a background check by using some resources that are available to me and found his arrest record and report of the incident. I picked them both up at the Burger King and brought them back to my place where Angela had been waiting. I had them sit on my couch. I began saying I not doing this to hurt anyone but I want some clarification as to the circumstances and the reason she decided to stay with this joker after hearing of this. I then showed the arrest report to (I'll call him Jose) Jose and the blood drew from his face. My daughter said How did u get that?. I replied what do I do for a living. I can find things about people. Jose explained it's all a misunderstanding with the girls parents. The girl was jelous that he was seeing another girl and wanted him to be her boyfriend so he rejected her she made this accusation. I was arrested and that stopped him from entering the Military(Airforce). My daughter became very upset and said everyone needs to stop involving themselves in her life. I explained to her I am very disappointed in her because I taught her better to involve herself with a criminal and that she is worth more than this piece of garbage. She actually befended him and thats when I knew she was hooked by him. I leaned toward him and said this "If ever you put a hand on her in anger I will kill you and your whole fucked up family" I know that is a threat but what is a father to do. He understood where I was coming from and there was an understanding. I have meet his alcoholic father and grandparents and let them know that I not someone to fool around with because I will do what I say if any harm comes to my daughter. Since then there has been no uproar from him or his family.