Theft over 500, and Thief is getting away!! Please help!?

On New Years Eve, a so called friend slept over , and stole my 7ct tw diamond bracelet valued at $3,500.00. I know she did it, because it was just her, myself and my 5 year old at home, and the house was armed. We all slept downstairs by the fireplace, and at 2:35AM in the morning when I got up to use the bathroom, I took off my bracelet and placed it along with my wedding ring on a table nearby the couch I was sleeping on. By 9:50AM, when she asked me to disarm the house so she could leave, it was then that I noticed my bracelet was gone. When I asked her if she had seen it she said no. So I pointed to my rings and said it was there with my rings, but she said she didn't have it. I had gotten up before her and my daughter, and went upstairs and it was still there. She had tidied up downstairs, yet she said she didn't see or take it. I know she had a motive because the day before she had played her account info and her bank was negative, and she had no money. When she tried to leave, I called the police, but when they arrived, they informed me that they couldn't search her. She wanted to fight me if I approached her, and because we were warned that if we didn't stop fussing back and forth social services would be called, I told her to get the hell out of my house. I filed a police report, and although they told me that it was quite suspicious regarding the cirstances, they said they would get her for questioning etc, and probably file charges for theft over $500, but it has been a week, and I think they just dropped the case. It is very difficult to just know that this girl took my property and is hamming it up scotch free. What can I do to have her prosecuted? I know she probably pawned my jewelery, but knowing her,she is wearing it and it is not hers. I wanted to give it to my daughter on her wedding day,and it was a gift from my husband. Please help!! Thank you!!