Criminal background tests can provide important information, but you need to also be aware of the limitations. Get the practical advice you need to know about criminal background checks.
http://www.criminalbackgroundtest.com/
A professional investigative agency dedicated to providing services throughout the world. Site is in Chinese and English.
http://www.pichina.com/
Provides live investigators that search for unlisted phone numbers, DMV / VIN information, cell phone records, and non-published addresses.
http://www.bestpeoplesearch.com/
Private investigation agency located in Madrid, Spain. In English and Spanish.
http://www.detectivecardenas.com/
Criminal background checks and other basic offline security data, accessible through a web interface for accessing facts necessary for better decision-making.
http://www.criminalreports.com/
Specializes in background checks, criminal records, security, surveillance and locates.
http://www.collintel.com/
California private investigators & Hawaii private investigators that run pre-employment background checks, handle screening & workers compensation; also providing arson & fire investigators.
http://www.cramerinvestigations.com/
Diversified Risk Management, Inc. is a nationwide provider of corporate investigation, workplace theft solutions and internal risk mitigation consulting services.
http://www.diversifiedriskmanagement.com/
Information regarding professional investigation technique. The tips the tricks the secrets revealed by the UK's most aggresive investigator.
http://www.dirtytricksmanual.com/
Investigation firm based in Vancouver, Canada. Features include glossary, services offered, and PI profiles.
http://www.fbig.ca/