Even though a nationwide criminal history search is practically impossible, many companies advertise that such a search can be made possible by hiring their services. Practically speaking, such a search would involve having access to records worldwide or at least access to the FBI database that houses national criminal records. This is an impossible task since the investigators would not have access to the records in each and every court in the country nor have access to the FBI records.

Most of the companies that claim to provide a nation wide search would be able to investigate the records in a few specific states as well as the data available online. This does not ensure accurate data when it comes to an extensive search.

The FBI houses the complete nationwide criminal records, but only a small part of it would be accessible to licensed investigators unless the background check is being conducted to catch a criminal. They also have records of the fingerprints of all criminals as well as normal citizens for reference. Hence, the investigators can get the FBI to compare a set of prints to find out if the individual has a criminal history even though they would be unable to access the records themselves.

Many websites claim to provide a nationwide pre-employment criminal search. Often, this returns accurate results but there are also cases when they are unable to check the records in all the states. This might prove to be dangerous in certain instances such as sexual harassment, drug abuse cases where the employer is unable to know about the applicants true nature. This might lead to problems later on in the future both to the employer, the company, and all the existing employees.

It is suggested to shop around for a good investigating agency before entering into a contract with them. This usually ensures accurate and correct information and would be of a big help in hiring an applicant for a post.