A DNA database is a collection of DNA profiles that can be used for various purposes, including criminal investigations, paternity testing, and medical research. These databases store genetic information obtained from blood, saliva, or other biological samples, allowing for the identification of individuals based on their unique DNA patterns. Law enforcement agencies often use DNA databases to solve crimes by matching DNA found at crime scenes with profiles of known offenders or unidentified individuals. In many countries, such as the United States, these databases are maintained by government agencies and can help in exonerating innocent people as well.