Collect any information that is already known about the missing person from relatives of the deceased person. Find the missing person's date of birth and birthplace, if possible. Look for information that might lead to a prior or current address.
Gather information about the deceased person that you can use to verify the family relationship when you find and contact people who might be the missing heir. For example, the missing heir should know some of the other relatives' names.
Type the person's name into search major search engines. Review the listings to see if anything comes up. Look for blogs, websites, newspaper articles that mention the missing person's name and location or phone number.
Search free online phone directories such as The Ultimate White Pages or Yahoo People Search. Type the name into Yahoo People Search and review the listings that come up to see if it is the same person. This search will provide phone numbers, addresses, websites and anything else on the Internet that includes the name.
Publish a classified advertisement in a local paper where you think the person might be located. The advertisement should state who you are searching for and why. If anyone responds, ask her questions about the deceased person to verify if she really is the heir.
Search free online people locators such as Spies Online or Skip Ease to find names, addresses and phone numbers. Type the name into social networking sites like MySpace.com, Facebook.com or LinkedIn.com. Send messages to people who might be the missing heir.
Use the contact information you have gathered to contact the person by letter or phone to find out if he is related to the deceased person.
Hire a private investigator or professional skip tracer who specializes in locating missing heirs if the free searches have failed.