The Department of Forensic Biology of the New York City Office of Chief Medical Examiner (OCME) performs the DNA testing for thousands of cases each year from all five boroughs of New York City. Cases range from homicides and sexual assaults to burglaries and robberies to the identification of unknown persons; the samples tested are typically blood and other body fluids, as well as epithelial cells or bone. The results of such testing can be used to link people to other people, people to crime scenes, or people to evidence. The majority of DNA cases are tested using short tandem repeat (STR) polymerase chain reaction (PCR) testing at 13 or more locations of nuclear DNA. When eligible, the DNA profiles generated are submitted to the national DNA database, to be compared to results from forensic labs across the state and across the country. Analysts from OCME provide expert witness testimony at court when necessary, to interpret their results for jurors. A review of the science involved in creating DNA profiles will be offered, as well as some cases which were solved using DNA testing.