How do I sue the police for slander and defamation?

I was stop for a minor traffic stop ( no ticket issued ) the police ask for driving license they ran a make on database I had a misdemeanor 15yrs ago for petty theft giving (community service and charges dismiss) the started telling my employer that I was committing crimes on job site saying that I stole purses and broke into cars something I am innocent of and never committed these crimes in my life! The police put me under investigations and could not place me at any crime scene times or dates my supervisor explain to me. I have found out that the police is going around the community with my picture and name telling people I am committing crimes. The police also is putting information on database I am finding during background checkes telling employes and my landlord that I am a suspect and person of interest. How do I sue them for smearing my name and defaming my character?