FBI Uniform Crime Reports (UCR) is one of the best tools for tracking crime trends in communities nationwide; FBI UCR data for 2014 is now available from the NICAR data library.
Law enforcement agencies around the country voluntarily submit reports to the FBI on what are known as "index" crimes: Murder, nonnegligent manslaughter, forcible rape, robbery, aggravated assault, burglary, larceny-theft, motor-vehicle theft and arson. These crimes are meant to serve as an index for gauging fluctuations in both the overall volume and rate of crime. The data include the number of crimes by agency and by month. Geographic information include region, state, county, city, and metropolitan statistical area (MSA).
UCR data can help you track different crimes in your community, as well as crime rates over time. Peruse IRE tipsheets for help: