Overview#Combined DNA Index System (CODIS) is the United States national DNA database created and maintained by the Federal Bureau of Investigation (FBI).
Combined DNA Index System Ldapwiki refers you to Wikipedia: Combined_DNA_Index_SystemUnited States federal government and many US State collects a DNA sample—no matter which agency does the collecting—the sample is sent to the FBI for storage, and the extracted profile is incorporated into the FBI’s massive CODIS database, which already contains over 13 million “offender” profiles (“detainees” are classified as “offenders”).
All US States perform collection upon conviction and most perform collection on felony arrests regardless of conviction.
It is next to impossible to get DNA expunged from the database, and once it’s in CODIS it is subject to repeated warrantless searches from all levels of US State and federal Law Enforcement Agency. Those searches have implicated people for crimes they didn’t commit.