As you can see from its timeline the only edit made to your question, prior to it being made a duplicate by another user, was by me, and that just added a tag. Consequently, the decision to make it a duplicate appears to have been made based on the original content of your question body.
I am very sorry for the loss of your wife nine years ago but I hope you will appreciate that we need to be very cautious on this site when dealing with questions that involve anyone born less than 100 years ago.
My later edit to remove the statement of urgency was to ensure that your question was treated on its technical merits within the scope of this site. We can take no responsibility for you having discarded your tax returns and not being able to find a death certificate.
I am not a US citizen but my understanding is that, as your late wife's spouse, you could contact the United States Social Security Administration (SSA) to obtain this information. It is they who are best placed to verify your identity, and entitlement to the information.
I believe our site has done its best to provide you with an answer within the guidelines and policies under which it operates.