Get Grandpa's FBI File is a great new website that makes easy the process of requesting FBI files under the Freedom of Information Act. You just fill out and submit a simple web form, and then you are practically done. The website generates the request letter(s) for you to print out, which you send to the appropriate FBI office, along with "proof of death." Don't know what "proof of death" is? GGFF will help you with that, too.
And just in case the site's title and catchy images lead you to think otherwise, I will add that you do not need to be related to the subject of your FOIA request. You can request FBI documents on anyone who is no longer living. You do not need to be related to or know the person.
There are, of course, all sorts of reasons why the FBI might have developed files on someone. To the four questions from the GGFF site, below, I would add, did Grandma Ella ever attend a meeting of the Student Nonviolent Coordinating Committee or organize a fund raiser for the National Association for the Advancement of Colored People? Politically active Black people have always been targets of the FBI.
Did Grandpa Joe run a gambling ring?
Did Aunt Mary ever lead an antiwar protest?
Did Cousin Gary smuggle booze during prohibition?
Was Great-Uncle Fred a communist organizer?