Several years ago I worked for an International School in Hong Kong that was in a historic building that was used by the Japanese in WW2 as “Police Headquarters” cum detention and torture center. The building had also been associated with the head of one of the “Tongs” from the 1920’s through the early 1980’s. There were rumors that there were several bodies buried in the court yard. I had to have some concrete poured to strengthen a floor in the back of my library. Before they put the linoleum down I took a chop stick and scratched “RIP J. Hoffa 14/2/14 - 15/8/75” I figured in 25 to 30 years when the linoleum was removed someone would see it.
Now, if only the Library of Congress and other document holders would publish / release the documents gathered for the assassination of John F. Kennedy.
My goodness.... it has been over fifty years.