How The US Can Help In Your Search
Finding someone in the US is not hugely complex. We have phonebooks, government websites, census data, and third party people search directories. Still unlisted numbers, relocation, and changes in name among other things can make things difficult. It is easy to understand that, but what you must also comprehend is that in other countries they may not organize or file data the same way we do in the USA. There is not an international standard for the way directory data is arranged. You must also remember in some countries middle and last names are structured differently as well.
If they are an American citizen overseas, the circumstances are much different. Their travels will have left a paper trail with not only the country’s customs or boarder authorities, but also with the US authorities as well. The US embassy in that country can help you in your search. This type of search technique is generally reserved for emergency use. If it is a person in the military or the Red Cross, the circumstances will differ slightly as well. USA.gov lists a few locator sources that could help.
The United States Department Bureau of Consular Affairs will assign an officer. Though they cannot give legal advice, or obtain physical custody, (in the event of a kidnapping or runaway) they can still help. More information can be found at http://travel.state.gov/travel/tips/emergencies/emergencies_1202.html