Jeopardizing a friendship to save a friend!

Ok so my ex best friend who I will not name now hates me and wishes harm on me because I told the police about something. She watches mentally disabled people through a local program. She is currently watching a girl who is on lots of different medications and is a diabetic. She told me that she has not given this girl who she is responsible for her medications for over a month. One day she told me that the girl was in the hospital for something to do with her diabetes. I told her many times before that she has to take this job of hers seriously because she is putting people's lives in danger because that girl is on those medications for a reason. My ex friend does not take anything seriously and I wanted this to be a wake up call for her before she ends up killing someone and going to jail. I wouldn't be able to live with myself if something happened and I knew about it and did nothing about it. My ex friend said that I picked that girl over our friendship. Which means that she doesn't even see that anything is her fault. All she thinks is that I'm out to get her when I'm not. I could have told them about a lot more things but Im not trying to end her I just want her to wake up and take responsibility for her actions before something irreversible happens and she has to pay the consequences. If i was out to get her I would have never told her I did it. I would have been anonymous. She says that Im talking bad about her but the only thing I did was tell the truth. I stand by what I did and I knew our friendship was in jeopardy but hey if this is what it takes to for her to grow up then so be it.