Unfortunately the reality of criminal searches is nothing like what it looks like on TV and there is no single source for every criminal record in the United States.
Even the FBI’s database, the National Crime Information Center, is not probable cause for a law enforcement agency to take action. Any positive NCIC response must be verified with the entering agency to make sure the information is accurate and up-to-date. Law enforcement systems are generally not accessible for most background screening purposes and contain information to assist law enforcement agencies with investigating criminal activity not information regarding criminal convictions.
Criminal justice systems, for example a county court, are the primary source for a criminal records search. When a case has been adjudicated in a court of law and the defendant has plead guilty or been found guilty by a judge or jury of their peers that is information that can be used in making a risk management decision. The organization of criminal courts vary state by state so the scope of a criminal search and the costs associated can vary as well.
There are data aggregators (aka wholesalers) that purchase or “screen scrape” criminal information from accessible courts and criminal justice agencies. These large databases can be a great way to supplement a criminal records search with data from many jurisdictions and agencies, but they also have significant limitations. Aggregated information is always out of date, many jurisdictions do not contribute data, records do not always contain personal identifiers to confirm who the record belongs to and incorrect information is often not updated or corrected. Many of these instant databases are available online for anyone to use, but most do not provide FCRA compliant results which is extremely important if your purpose behind pulling the information could adversely impact a consumer.