Not in the Social Security Death Index (SSDI)?

Perhaps in your search for vital records, your deceased answer is not included in the SSDI? Maybe they died prior to 1962, or their death was not reported to the SSDI? It is still possible that they may have, at some time, applied for a Social Security Card? If they did, then you may be able to obtain a copy of their SS-5? The SS-5 forms were first introduced in 1936. You will need to provide the Social Security Administration with proof of death. For details refer…. … The Social Security Administration’s Guide to Freedom of Information Act Requests

Note: Social Security payments were first instituted around 1940. As a result the Social Security Administration has virtually no information about people who died prior to this time. The majority of the SSDI vital records cover the period 1962 to 1988. There are some entries of people who died between 1940 and 1961. This data base is a rich source of information for those involved in geneology.

(You will need to search state listings for death indexes for pre 1962 deaths.)