Google it and you will find many sites offering a “National arrest and criminal check” for $12.95, etc. The problem with this is that no such search exists, regardless of the amount of money you spend. It is a myth.
The only national criminal check is through the National Criminal Information System. This system is maintained by the Federal Bureau of Investigation and accessible by all law enforcement agencies across the U.S. The same law enforcement agencies contribute to the system with criminals and crimes occurring in their jurisdiction. It is a wonderful system for a background researcher but a felony to access and use information from the system that is not official law enforcement business. Many law enforcement personnel have been charged criminally and lost careers for selling information from the NCIC system.
There are exclusive partial, national criminal databases that cover more than have of the country and we use this for our criminal research. They key is knowing what you are getting; which counties and states are in the system and whether it is current or historical records. We know.
In regards to any records research, keep in mind that there is a huge difference between No Record and “No Record Found.” Use only trusted sources for your research.