Someone called my work and accused me of being a drug addict,theif, and stealing narcotics from work!?

I have been an LPN for 22 years. I have been at this-job since February of 2009. The social worker took the call wrote everything down that the caller had said then she signed it and wrote the time. I was off work for 3 days and returned on a tuesday. I was starting my med p when I was called into the office and was shown the letter. I was taken to the E,R for a drug test and alcohol test and was told not to return to work until they call me. They called me on Friday to return to work on Saturday which I did. Problem is management continues to find mistakes andI am the first one they look at. If some one had done the mistake its O well. My employment never called the police or sheriff department to report the incident. I have no idea whats in my file they seem to be to busy to show me. Is their anything I can do? Or do I just go to work and be on pins and needles? I have a clean work history. I told the company my husband was wanted by the US Marshalls for violation of parole. He is a white collar criminal.