One of my favorite sites available for research is FINDAGRAVE.COM. It is a free site that helps you locate cemetery records. The site is totally dependent on volunteers so it's not complete. You can locate the graves of famous people as well. It is very simple to use, you just need to know the city and county that you are looking for.
Cemetery records and headstones can give you information that you may not have found otherwise. Volunteers may even take a picture of a headstone for you. It is a great resource for genealogical research. You can also add information and pictures to share with others.
To search, use this link. Enter as much information as you know and see what you find. Remember, if you don't find someone it doesn't mean they aren't there. That cemetery may not be indexed yet.
I searched Thomas Bowen Riley and this is what came up:
Birth Jan 15,1921
Death July 27, 1999
Maj, US Army
Riverside National Cemetery
Plot: 2A,0, 1196
There is no individual headstone photo but it give the plot info. I could post a request and maybe someone would take a picture for me.