This is a fragment of a "report" a student sent me. I would appreciate any information on the veracity of this story: Note: There is substantial evidence to say that the fourth shot was fired from atop the Dallas County Records Building. In 1975, a maintenance worker named Morgan found a spent 30.06 shell casing under a lip of tar on the roof of the Records Building. The casing had apparently been there for a long period of time, and showed evidence of use of a “sabot slug”. “Sabot” slugs are u