Ask the person where he works. You can Google the person's name. If the person has a common name, try including a state or city name in your search. Many companies will list their employees' names on their websites and searching the Web can help retrieve the information. A private investigator can easily determine where a person works. All you have to do is tell them who you want information on and hand over the cash. Sign up for a background check website. There are countless websites designed for private investigators and or employers that want to look into a person's past.