Jim Koethe *
one of the men in Ruby's apartment

Jim Koethe was one of three journalists who were allowed into Jack Ruby's apartment by his roommate George Senator following his killing of Lee Oswald. He died of a karate chop to the neck, but it was not ruled as murder. He was working on a book about the assassination at the time - but his notes were never found.
Neither of the other two writers, Tom Howard and Bill Hunter lived much longer.